Frederico Miguel do Ceu Marques dos Santos
@isec.pt
Scopus Publications
Scholar Citations
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Scopus Publications
Luis Roseiro, Tomás Ribeiro, Marco Silva, Frederico Santos, Alexandra André, Ruben Durães, William Xavier, Arménio Cruz, and Cândida Malça
Springer Nature Switzerland
C. Malça, T. Ribeiro, M. Silva, F. Santos, R. Bernardes, A. Cruz, W. Xavier, R. Durães, and L. Roseiro
Springer Nature Switzerland
T. Ribeiro, L. Roseiro, M. Silva, F. Santos, R. Bernardes, R. Cardoso, V. Parola, H. Neves, A. Cruz, W. Xavier,et al.
Springer Nature Switzerland
Marco Tomé, Pedro Beirão, Luis Roseiro, and Frederico Santos
SAGE Publications
All around the world, modern elevators transport safely and comfortably millions of passengers and freight each day. Since modern elevators emerged at the beginning of the 19th century, several advances have risen in this transportation system. Among them, safety conditions were significantly improved. Therefore, modern elevators must be equipped with safety protection systems to assure safety conditions and avoid accidents. An overspeed governor is one of the components of such a safety system. It acts as a stopping mechanism when the elevator car reaches an excessive velocity, known as tripping speed. When the tripping speed is reached, the overspeed governor is mechanically locked and halts the rope, thus stopping the elevator car. This paper describes the development of a new measuring system able to measure the trigger velocity of an overspeed governor with the help of a graphical interface available on a mobile electronic device (smartphone or tablet). Practical application: A new overspeed governor velocity measuring system uses a mobile electronic device for non-contact velocity measurement. This new process may replace the inaccurate measuring system currently employed by maintenance technicians, thus increasing its reliability. The main objective consists of rigorously testing the operation of overspeed governors. The developed system guarantees the automatic execution of the test under several anomalous operating situations, thus allowing the user to have real-time access to the test data obtained through a graphical interface available on a mobile electronic device.
Pedro Amaro and Frederico Santos
Elsevier
João Cunha, João Durães, Ana Alves, Fernanda Coutinho, Jorge Barreiros, José Pedro Amaro, Marco Silva, and Frederico Santos
MDPI AG
Digital transformation has increased the demand for skilled Information Technology (IT) professionals, to an extent that universities cannot satisfy it with newly graduated students. Furthermore, the economical downturn has created difficulties and scarcity of opportunities in other areas of activity. This combination of factors led to the need to consider requalification programmes that enable individuals with diverse specialisations and backgrounds to realign their careers to the IT area. This has led to the creation of many coding bootcamps, providing intensive full-time courses focused on unemployed people or unhappy with their jobs, and individuals seeking a career change. A multidisciplinary group of higher education teachers, in collaboration with several industry stakeholders, have designed and promoted an embedded systems programming course, using an intensive project-based learning approach comprising 6 months of daylong classes and a 9 months internship. Having finished two editions of the programme, a questionnaire was presented to the students that finished successfully, in order to evaluate the long-term benefits to graduates and companies. This paper presents a brief discussion of the programme organisation and pedagogical methodologies, as well as the results of the questionnaire, conducted following a Goal–Question–Metric (GQM) approach. The results demonstrate very positive outcomes, both for graduates and companies.
Aqsa Aslam, Frederico Santos, and Luis Almeida
IEEE
Platooning is a promising concept used within the Intelligent Transportation System to increase efficiency and safety of road transportation. It is based on periodically sharing the kinematic status of the platoon members to allow reducing inter-vehicle distances in a safe way. This coordination is automatic and depends heavily on the wireless channel. A common technique to improve the channel properties is to use Time-Division Multiple Access (TDMA) that organizes the access to the wireless medium in slots assigned exclusively to each vehicle. However, while platoons are physical and dynamic, the corresponding dynamic reconfiguration of a logical TDMA frame is non-trivial. In this paper we address this Cyber-Physical problem resorting to the RA-TDMAp protocol to track the dynamics of a platoon, specifically joining, merging and leaving. In our solution, we include an adequate admission control block, to verify whether joining or merging can be accepted, and we present the state-machine that handles the reconfiguration process. We validate our TDMA reconfiguration mechanism with simulations using the Plexe/Vein/OMNeT++ framework. We show the effectiveness of the proposed mechanisms which ensures a synchronized start of the platoon control with the TDMA frame reconfiguration.
J. Amaro, J. Barreiros, F. Coutinho, J. Durães, Frederico Santos, Ana Alves, Marco Silva and J. Cunha
Due to the proliferation of IT companies developing web and mobile applications, computer programmers are in such high demand that universities can’t satisfy it with newly graduated students. In response, some organisations started to create coding bootcamps, providing intensive full-time courses focused on unemployed people or individuals seeking for a career change. There is, however, a different set of skills that is becoming increasingly required, but is not addressed by those courses: embedded programming. In fact, the Internet of Things is connecting every device to the internet, thus making knowledge on hardware and C/C++ programming very relevant skills. A group of computer science and electrical engineering university teachers, in collaboration with several industry stakeholders, have promoted an embedded systems programming course in C and C++. This course is based on an intensive project-based approach comprising 6 months of daylong classes followed by 9 months of paid internships. After two editions, thirty embedded programmers, with no relevant previous programming experience, have been placed with the partners’ working force. In this paper, the course organisation and pedagogical methodologies are described. Problems, challenges and adopted solutions are presented and analysed. We conclude that in spite of the intense rhythm and demanding nature of the subject matter, it is possible to find the structure and solutions that keep students engaged and motivated throughout the course, allowing them to gain the required competences and successfully transition into a new career path.
Aqsa Aslam, Pedro M. Santos, Frederico Santos, and Luís Almeida
MDPI AG
Vehicular ad-hoc networks (VANET) enable vehicles to exchange information on traffic conditions, dynamic status and localization, to enhance road safety and transportation efficiency. A typical VANET application is platooning, which can take advantage of exchanging information on speed, heading and position to allow shorter inter-vehicle distances without compromising safety. However, the platooning performance depends drastically on the quality of the communication channel, which in turn is highly influenced by the medium access control protocol (MAC). Currently, VANETs use the IEEE 802.11p MAC, which follows a carrier sense multiple access with collision avoidance (CSMA/CA) policy that is prone to collisions and degrades significantly with network load. This has led to recent proposals for a time-division multiple access (TDMA)-based MAC that synchronize vehicles’ beacons to prevent or reduce collisions. In this paper, we take CSMA/CA and two TDMA-based overlay protocols, i.e., deployed over CSMA/CA, namely PLEXE-slotted and RA-TDMAp, and carry out extensive simulations with varying platoon sizes, number of occupied lanes and transmit power to deduce empirical models that provide estimates of average number of collisions per second and average busy time ratio. In particular, we show that these estimates can be obtained from observing the number of radio-frequency (RF) neighbours, i.e., number of distinct sources of the packets received by each vehicle per time unit. These estimates can enhance the online adaptation of distributed applications, particularly platooning control, to varying conditions of the communication channel.
Carlos Pereira, João Mesquita, Diana Guimarães, Frederico Santos, Luis Almeida, and Ana Aguiar
MDPI AG
Due to multiple reasons, emergency wards can become overloaded with patients, some of which can be in critical health conditions. To improve the emergency service and avoid deaths and serious adverse events that could be potentially prevented, it is mandatory to do a continuous monitoring of patients physiological parameters. This is a good fit for Internet of Things (IoT) technology, but the scenario imposes hard constraints on autonomy, connectivity, interoperability, and delay. In this paper, we propose a full Internet-based architecture using open protocols from the wearable sensors up to the monitoring system. Particularly, we use low-cost and low-power WiFi-enabled wearable physiological sensors that connect directly to the Internet infrastructure and run open communication protocols, namely, oneM2M. At the upper end, our architecture relies on openEHR for data semantics, storage, and monitoring. Overall, we show the feasibility of our open IoT architecture exhibiting 20–50 ms end-to-end latency and 30–50 h sensor autonomy at a fraction of the cost of current non-interoperable vertical solutions.
N. M. Fonseca Ferreira, Marco Silva, Victor D.N. Santos, Frederico Miguel Santos, J. Candido B. Santos, and Joao P. Ferreira
IEEE
This paper presents the exciting use of robotics to teach technologies in an approach that motivates the students through intuitive learning. MSc degree programme students are engaged in strong team-building, while developing and testing new algorithms for mobile robotics and electronics areas. This project endows students with intuitive learning, and experimental results revealed that the integration of skills allows the students to develop applications for real scenarios. In this work it is described an application to control with hand gestures, several differential driven robots.
Victor D. N. Santos, Nuno Miguel Fonseca Ferreira, J. Cândido B. Santos, Frederico Miguel Santos, Fernando D. Moita, João P. Ferreira, and Marco Silva
Springer International Publishing
Nuno M. Fonseca Ferreira, Fernando Moita, Victor D. N. Santos, João Ferreira, João Cândido Santos, Frederico Santos, and Marco Silva
Springer International Publishing
Joao Mesquita, Diana Guimaraes, Carlos Pereira, Frederico Santos, and Luis Almeida
IEEE
The Internet of Things (IoT) is experiencing rapid growth and being adopted across multiple domains. For example, in industry it supports the connectivity needed to integrate smart machines, components and products in the ongoing Industry 4.0 trend. However, there is a myriad of communication technologies that complicate the needed integration, requiring gateways to connect to the Internet. Conversely, using IEEE 802.11 (WiFi) devices can connect to existing WiFi infrastructures directly and access the Internet with shorter communication delays and lower system cost. However, WiFi is energy consuming, impacting autonomy of the end devices. In this work we characterize a recent WiFi-enabled device, namely the ESP8266 module, that is low cost and branded as ultra-low-power, but whose performance for IoT applications is still undocumented. We explore the built-in sleep modes and we measure the impact of infrastructure parameters beacon interval and DTIM period on energy consumption, as well as packet delivery ratio and received signal strength as a function of distance and module antenna orientation to assert area coverage. The ESP8266 module showed suitability for battery powered IoT applications that allow 2–4 days recharge cycles on a 1000mAh battery with seconds-scale transmission intervals.
Carlos Pereira, Diana Guimaraes, Joao Mesquita, Frederico Santos, Luis Almeida, and Ana Aguiar
IEEE
Machine-to-Machine (M2M) communications are a key enabler of Internet of Things (IoT) applications. One domain with growing interest in M2M/IoT is e-health, either for self-monitoring, home monitoring, or hospital systems. However, current sensing devices in this domain rely on short-range communication protocols that require a gateway (GW) for Internet connection. Smartphones have been proposed as GWs in mobile M2M communications due to their enhanced connectivity and sensing capabilities. However, the GW functionality impacts on the smartphone usability, causing undesirable battery depletion and the smartphone itself increases the overall cost of e- health solutions. In this work, we propose converging e-health devices and Wi-Fi towards direct Internet access through the existing Wi-Fi infrastructure and by-passing current GWs. We use recent low-cost ultra low-power Wi-Fi modules and feature them with M2M capabilities supporting their integration in an interoperable e-health framework. We present results on end-to-end latency and power requirements within a concrete e-health use case that show the feasibility of the proposed GW-less solution.
Aqsa Aslam, Luis Almeida, and Frederico Santos
IEEE
Vehicular networks are a core component in Intelligent Transportation Systems (ITS) enabling communication among vehicles for collaborative applications. One example of such an application that may bring benefits in reducing travel time, fuel consumption and improving safety is platooning. This application coordinates a group of vehicles that travel together, doing automatic control of inter-distances and speeds [1]. A critical part of this application is the vehicle-to-vehicle (V2V) communication highlighting the importance of improving the channel quality. Existing ITS standards, namely WAVE (USA) and ITS-G5 (Europe), use IEEE 802.11p DSRC (Dedicated Short-Range Communication) [2] that relies on CSMA/CA distributed access arbitration. Despite the Collision Avoidance attribute collisions can still occur and the channel quality can degrade significantly in dense traffic environments.
Aqsa Aslam, Luis Almeida, and Frederico Santos
Springer International Publishing
Aqsa Aslam, Luis Almeida, and Frederico Santos
IEEE
Vehicular Ad-hoc Networks (VANETs) have a significant potential to enable new applications among multiple types of vehicles. In these networks, the Medium Access Control (MAC) plays an important role in providing an efficient communication channel. Currently, existing standards use the PHY and MAC of IEEE 802.11p, which is fully distributed and based on Carrier Sense Multiple Access with collision Avoidance (CSMA/CA), thus still prone to collisions. This has led to recent proposals for TDMA-based overlay protocols to prevent collisions, including one based on Reconfigurable and Adaptive TDMA (RA-TDMA). This protocol sets a TDMA round allocating slots to the nodes engaged in a given collaborative application, only, e.g., a platoon or a multimedia group. Then, other traffic, including from other TDMA rounds of concurrent applications can co-exist in space and time using the native CSMA/CA mechanism of IEEE 802.11p and the synchronization mechanism of RA-TDMA. In this paper, we do a qualitative comparison among TDMA protocols in VANETs showing the advantages of RA-TDMA. Early experimental results validate the capacity of RA-TDMA to support multiple concurrent rounds in a scalable manner.
Luis Almeida, Frederico Santos, and Luis Oliveira
Springer International Publishing
Luis Almeida, Frederico Santos, and Luis Oliveira
Springer International Publishing
Luis Oliveira, Luis Almeida, and Frederico Santos
Springer Berlin Heidelberg
Frederico Santos, Luís Almeida, Luís Seabra Lopes, José Luís Azevedo, and M. Bernardo Cunha
Springer Berlin Heidelberg
Joao P. Trovao, Frederico M. Santos, Marco J. Silva, and Humberto M. Jorge
IEEE
This article presents an Ethernet remote monitoring system for electric industrial power distributions. This system permits monitoring through the spread of low cost remote platforms, with synchronous acquisition, Ethernet communication, computational analysis programs, statistical treatment and creation of automatic reports. The dissemination of this system allows a fast and systematic approach to the harmonics disturbances problematic. It has the capability to remotely study the propagation of these disturbances in the industrial installations, to determine waveform distortion caused by harmonics sources, to quantify the impact of these disturbances and to elaborate daily quality indexes reports (IEEE Standard 519-1992) based on recent harmonics analysis techniques. This paper describes the hardware prototype of the data acquisition system architecture for power quality monitoring and analysis. The prototype was validated by statistical procedure and are presented experimental results made in real industrial plant, proving the system viability and value added in this problematic area.