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Uma pessoa gastaria 82 anos de vida para visualizar todos os vídeos que são publicados no Youtube durante um único dia. O tráfego gerado pelos telemóveis cresce duma forma continuada devido às redes sociais e à partilha de vídeos na Internet. As redes de telecomunicações são a espinha dorsal da sociedade da informação em que vivemos. O fenómeno das redes sociais e do Youtube só foi possível graças à quarta geração móvel (4G), disponível a partir do ano 2010. Com o 4G foi possível atingir velocidades médias de acesso à Internet de 50 Mbit/s, na maior parte das zonas urbanas, o que permite, uma qualidade de experiência na partilha de conteúdos multimédia quase instantânea.
O Programa de Recuperação e Resiliência
(PRR), apresentado à Comissão Europeia
pelo Governo, enquadra-se no mecanismo
extraordinário NEXT GENERATION EU
criado em resposta à crise causada pela
pandemia COVID19 e que será utilizado
pela primeira vez na história da União
Europeia. O PRR é um programa com
um período de execução até 2026,
e vai implementar um conjunto de
investimentos no valor de 16,4 mil M€.
Durante os próximos seis anos o PRR
fará fluir meios numa dimensão sem
precedentes para a modernização e o
desenvolvimento económico e social de
Portugal. O PRR está organizado em 3
dimensões estruturantes: a Resiliência, a
Transição Climática e a Transição Digital,
num total de 20 componentes e 83
investimentos.
Contém referências bibliográficas
Trabalho por turnos ou escalas
Tese de doutoramento em Engenharia Electrotécnica, Universidade de Aveiro, 2007
Tese de doutoramento em Engenharia Electrotécnica, Universidade de Aveiro, 2007
Relatório do Trabalho de Fim de Curso de Engenharia de Produção Agrícola.
Disponível na Biblioteca da ESACB na cota C30-13221TFCPAN.
Atualmente em Portugal, à semelhança do que se
passa um pouco por todo o mundo, os operadores
móveis estão a implementar no terreno a rede móvel
4G. A tecnologia 4G baseia-se no standard LTE.
A rede 4G permite nas melhores condições
um acesso à Internet móvel de banda larga até
aos 50 Mbps. Com estas velocidades de acesso,
complementadas com a tecnologia wireless WiFi
conseguimos ter acesso quase instantâneo
à informação na ponta dos dedos através
dos tablets e smartphones. A evolução da rede tem
sido acompanhada com a redução do custo
dos telemóveis, cada vez com mais capacidade
de processamento e de memória, graças aos
avançados tecnológicos da micro-eletrónica.
Entretanto, milhares de aplicações móveis, muitas
baseadas em Android, apareceram graças
à imaginação dos engenheiros de software que tiram
partido da capacidade da rede 4G.
O tráfego de dados nas redes móveis cresceu 70%
só de 2013 para 2014, muito devido às aplicações
de vídeo (Youtube) e às redes sociais.
No âmbito da "campanha Cerâmica", promovida pelo Instituto de Desenvolvimento e Inspeçcão das Condições de Trabalho (IDICT), foi desenvolvido o sistema SEMIC. O SEMIC é uma ferramenta eletrónica para monitorização remota de parâmetros ambientassem postos de trabalho. Depois de instalado numa unidade fabril, o SEMIC permite realizar medidas de uma forma contínua e sem intervenção humana. O SEMIC integra numa única solução a monitorização do empoeiramento, temperatura, humidade relativa e nível de ruído acústico (intensidade e frequência), de forma a facilitar o trabalho dos técnicos de higiene e segurança.
This paper describes outdoor field measurements in television white spaces (TVWS) carried out in Munich, Germany. Fixed and mobile measurements in rural, sub-urban and urban scenarios showed that the modified
Hata model is appropriate to describe the path loss over distances up to few kilometers, and may be used in the process to populate a geo-location database.
“Copyright © [2012] IEEE. Reprinted from IEEE International Conference on Communications – ICC’2012. ISBN: 978-1-4577-2052-9 This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”
“Copyright © [2011] IEEE. Reprinted from ICT Future Network & Mobile Summit 2011. ISBN: 978-1-4577-0928-9.
This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”
Abstract: This paper describes a real case implementation of an automatic pedestrian-detection
solution, implemented in the city of Aveiro, Portugal, using affordable LiDAR technology and open,
publicly available, pedestrian-detection frameworks based on machine-learning algorithms. The
presented solution makes it possible to anonymously identify pedestrians, and extract associated
information such as position, walking velocity and direction in certain areas of interest such as
pedestrian crossings or other points of interest in a smart-city context. All data computation (3D
point-cloud processing) is performed at edge nodes, consisting of NVIDIA Jetson Nano and Xavier
platforms, which ingest 3D point clouds from Velodyne VLP-16 LiDARs. High-performance real-time
computation is possible at these edge nodes through CUDA-enabled GPU-accelerated computations.
The MQTT protocol is used to interconnect publishers (edge nodes) with consumers (the smartcity
platform). The results show that using currently affordable LiDAR sensors in a smart-city
context, despite the advertising characteristics referring to having a range of up to 100 m, presents
great challenges for the automatic detection of objects at these distances. The authors were able to
efficiently detect pedestrians up to 15 m away, depending on the sensor height and tilt. Based on the
implementation challenges, the authors present usage recommendations to get the most out of the
used technologies.
This paper describes the implementation and the technical specifications of a geolocation database assisted by a spectrum-monitoring outdoor network. The geolocation database is populated according to Electronic
Communications Committee (ECC) report 186 methodology. The application programming interface (API) between the sensor network and the geolocation database implements an effective and secure connection to successfully gather sensing data and sends it to the geolocation database for post-processing. On the other hand, the testbed allows authorized TV white space devices to gain access to the services of the geolocation database, according to a draft implementation of Internet Engineering Task Force (IETF) Protocol to Access White Space (PAWS) Two experimental methodologies are available with the testbed: one focused on coexistence studies with commercial wireless microphones, when the testbed is used for sensing only, and another for demonstration purposes, when the testbed is also used to emulate wireless microphone signals. Overall, this hybrid approach is a promising solution for the effective use of TV white spaces and for the coexistence with digital TV broadcast signals, or dynamic incumbent systems, such as unregistered wireless microphones.
“© 2018 IEEE. Personal use of this material is permitted. Permission
from IEEE must be obtained for all other uses, in any current or future
media, including reprinting/republishing this material for advertising or
promotional purposes, creating new collective works, for resale or
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The rapidly increasing popularity of WiFi has
created unprecedented levels of congestion in the unlicensed
frequency bands, especially in densely populated urban areas.
This results mainly because of the uncoordinated operation and
the unmanaged interference between WiFi access points. In this
context, the main objective of this experiment is to assess the
benefit of a coordinated management of radio resources in dense
WiFi networks for both 2.4 GHz and 5 GHz bands, using
Radio Environment Maps (REM). This experiment has used the
w-iLab.t test environment and the portable test-bed provided by
iMINDS for indoor scenarios. It was shown that REMs can detect
the presence of interfering links on the network (co-channel
or adjacent channel interference), and a suitable coordination
strategy can use this information to reconfigure Access Points
(AP) channel assignment and re-establish the client connection.
The coordination strategy almost double the capacity of a WiFi
link under strong co–channel interference, from 6.8 Mbps to
11.8 Mbps, increasing the aggregate throughput of the network
from 58.7 Mbps to 71.5 Mbps. However, this gain comes with
the cost of a relatively high-density network of spectrum sensors,
increasing the cost of deployment. The technique of AP handoff
was tested to balance the load form one AP to another,
although the aggregate throughput is lower after load balancing.
REMs are also capable of detecting coverage holes on the
network, and a suitable Radio Resource Management strategy
use this information to reconfigure the APs transmit power to reestablish
the client connection and increase the throughput of the
overloaded AP, at a cost of diminishing the aggregate throughput
of the network. The insights coming out from this experiment
helped to understand the opportunities and limitations of WiFi
coordination strategies in realistic scenarios.
“This is a pre-copyedited version of a contribution published in Marques P., Radwan A., Mumtaz S., Noguet D., Rodriguez J., Gundlach M. (eds) Cognitive Radio Oriented Wireless Networks published by Springer. The definitive authenticated version is available online via https://doi.org/10.1007/978-3-319-76207-4_23 "
This work focuses on the evaluation of blind sensing techniques for the detection of multiple wireless microphones in the UHF band, by means of simulation. The metrics used for the comparisons include probability of detection, probability of false alarm and minimum SNR detected for a given observation time. As an example, simulation results showed that blind detection algorithms can sense multiple wireless microphone signals with SNR = -19 dB, in a Rayleigh channel environment, considering 100 ms sensing time, 90 % probability of detection and 10 % probability of false alarm. In these conditions, blind detection techniques suffer maximum SNR degradation of 3.5 dB, as compared with single wireless microphone scenarios.
This paper presents the development of a bin-picking solution based on low-cost vision systems for the manipulation of automotive electrical connectors using machine learning techniques. The automotive sector has always been in a state of constant growth and change, which also implies constant challenges in the wire harnesses sector, and the emerging growth of electric cars is proof of this and represents a challenge for the industry. Traditionally, this sector is based on strong human work manufacturing and the need arises to make the digital transition, supported in the context of Industry 4.0, allowing the automation of processes and freeing operators for other activities with more added value. Depending on the car model and its feature packs, a connector can interface with a different number of wires, but the connector holes are the same. Holes not connected with wires need to be sealed, mainly to guarantee the tightness of the cable. Seals are inserted manually or, more recently, through robotic stations. Due to the huge variety of references and connector configurations, layout errors sometimes occur during seal insertion due to changed references or problems with the seal insertion machine. Consequently, faulty connectors are dumped into boxes, piling up different types of references. These connectors are not trash and need to be reused. This article proposes a bin-picking solution for classification, selection and separation, using a two-finger gripper, of these connectors for reuse in a new operation of removal and insertion of seals. Connectors are identified through a 3D vision system, consisting of an Intel RealSense camera for object depth information and the YOLOv5 algorithm for object classification. The advantage of this approach over other solutions is the ability to accurately detect and grasp small objects through a low-cost 3D camera even when the image resolution is low, benefiting from the power of machine learning algorithms.
Com o switch off da televisão analógica libertou-se uma importante e útil parte do espectro que possui
características que o tornam bastante importante e útil para utilização por outros sistemas radiofrequência. Mas é também nesta banda de espectro que funcionam inúmeros dispositivos sem fios, de forma anárquica, e sem qualquer tipo de regulamentação. Desta forma tornou-se necessário regular estes aparelhos. Neste artigo propõe-se uma plataforma que possibilita a regulamentação e correcta utilização destes dispositivos que operam anarquicamente nestas frequências.
“Copyright © [2012] IEEE. Reprinted from ICT Future Network & Mobile Summit 2012. ISBN: 978-1-4673-0320-0.
This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”
This paper presents a counting system project for the Naturtejo Global Geopark, which is structured in two phases. The objective of the first phase was to develop, install and test an electronic system able to remotely count the number of visitors on the Naturtejo Geopark walking routes and touristic sites. The data is reported through a web interface. A Pilot test is currently installed on Trail PR3 – “Fossil’s Route”, near the village of Penha Garcia. Since May 2015, more than 6000 tourists where monitored. The second phase of the project aims to track tourists based on the detection of Wi-Fi signals generated by their smartphones. Thanks to data mining algorithms, useful insights can be extracted that helps to understand the behaviour of tourists when they travel around the large territory of the Geopark.
This chapter describes outdoor transmission tests and field measurements in TV white spaces (TVWS) carried out in Europe. TVWS Measurements in Germany showed that the extended Hata model is appropriate to describe the path loss over distances up to a few kilometers. During the TVWS trial in Slovenia, we combine infrastructure sensing with geo-location database access to protect not only DVB-T, but also wireless microphone (WM) signals from TVWS devices interference.
“© 2017 IEEE. Personal use of this material is permitted. Permission
from IEEE must be obtained for all other uses, in any current or future
media, including reprinting/republishing this material for advertising or
promotional purposes, creating new collective works, for resale or
redistribution to servers or lists, or reuse of any copyrighted
component of this work in other works.”
“© © 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”
The concept of smart cities grew with the need to rethink the use of urban spaces based
on the constant technological advances and respecting sustainability. Today the urbanism and the
methodologies to think about the city are changing, as citizens want more access to digital
information on almost everything. Therefore, cities need to be planned and equipped with
infrastructures that enable connectivity between the citizens’ devices and the digital information.
This challenge raises technological problems, such as traffic management, in an attempt to
guarantee fair network access to all users. Solutions based on wireless resource management and
self-organizing networks are key when design the connectivity for these smart cities. This paper
presents a study on forecasting the daily load of Wi-Fi city hotspots, taking also in consideration the
weather conditions. This is particularly interesting to predict the network load and resource
requirements needed to ensure proper quality of service is provided to the hotspot users. The study
was performed in a Wi-Fi hotspot located in the city of Castelo Branco, Portugal. The results show
the ARIMA model is capable of identifying and forecasting seasonality events for one week in
advance including its capability to correlate the number of hotspot users with weather conditions.
This chapter provides an overview on European Telecommunications Standards Institute (ETSI) activities related to opportunistic spectrum sharing technology with a specific focus on (TV) white spaces. Key use cases are outlined and a novel approach for a coordinated and an uncoordinated approach for accessing the spectrum resource is given. A spectrum coordinator is indeed introduced in order to handle resource management. Furthermore, database system design and inter-database communication solutions are discussed as they are introduced by ETSI. Finally, various sensing mechanisms are detailed, which allow to monitor the radio environment and to feed decision-making components correspondingly.
“Copyright © [2014] IEEE. Reprinted from 1st International Workshop on Cognitive Cellular Systems 2014 . ISBN: 978-1-4799-4139-1 .This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”
“Copyright © [2015] IEEE. Reprinted from Vehicular Technology Conference (VTC Spring), 2015 IEEE 81st. ISBN: 978-1-4799-8088-8.
This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”
