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Os sistemas de bloqueio e filtragem de conteúdos Web encontram-se maioritariamente associados a regimes políticos opressivos, cujo principal objectivo na sua utilização é a censura. Infelizmente, este tipo de aplicação não só limita os direitos dos utilizadores como revoga o princípio daquilo que é uma rede global de partilha de informação pública, a Internet. Não obstante a filtragem e bloqueio de conteúdos Web é uma área franca em proliferação, cuja a sua correcta utilização tem vindo a demonstrar-se extremamente benéfica em determinadas áreas como a detecção e bloqueio de conteúdos pedófilos. Neste artigo apresentamos o protótipo Sisbloque, um sistema de filtragem e bloqueio de conteúdos Web projectado para ser implementado sobretudo em ISPs (Internet Service Providers), grandes instituições ou companhias, que propõe não só um mecanismo de filtragem de conteúdos com novas técnicas aperfeiçoadas e inovadoras como a intersecção de conteúdos relativos bem como a garantia de execução transparente suportada por um mecanismo de manipulação de erros.
info:eu-repo/semantics/publishedVersion
“Copyright © [2008] IEEE. Reprinted from International Conference on Communication Theory, Reliability, and Quality of Service, 2008. CTRQ '08. ISBN:978-0-7695-3190-8. 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.”
“This is a post-peer-review, pre-copyedit version of an article published in Intelligent Technologies for Internet of Vehicles. The final authenticated version is available online at: https://doi.org/10.1007/978-3-030-76493-7_14”.
“Copyright © [2009] IEEE. Reprinted from Next Generation Internet Network. NGI '09). ISBN:978-1-4244-4244-7. 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.”
Vehicular Delay-Tolerant Network (VDTN) appears as a particular application of the Delay-Tolerant Network (DTN) concept to transit networks. In this paper we analyze the use of a VDTN to provide asynchronous Internet access on a rural remote region scenario. Through simulation we evaluate the impact of a shortest path based movement model on the performance of four DTN routing protocols in respect to message delivery probability and message average delay.
“Copyright © [2009] IEEE. Reprinted from 17th International Conference on Software, Telecommunications & Computer Networks, 2009. SoftCOM 2009.ISBN:978-1-4244-4973-6. 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 © [2009] IEEE. Reprinted from Second International Conference on Communication Theory Reliability, and Quality of Service, 2009. CTRQ'09. ISBN:978-1-4244-4423-6. 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 © [2009] IEEE. Reprinted from Fourteenth IEEE Symposium on Computers and Communications (ISCC’09.ISSN:1530-1346. 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.”
Vehicular Delay-Tolerant Networking (VDTN) was proposed as a new variant of a delay/disruptive-tolerant network, designed for vehicular networks. These networks are subject to several limitations including short contact durations, connectivity disruptions, network partitions, intermittent connectivity, and long delays. To address these connectivity issues, an asynchronous, store-carry-and-forward paradigm is combined with opportunistic bundle replication, to achieve multi-hop data delivery. Since VDTN networks are resource-constrained, for example in terms of communication bandwidth and storage capacity, a key challenge is to provide scheduling and dropping policies that can improve the overall performance of the network. This paper investigates the efficiency and tradeoffs of several scheduling and dropping policies enforced in a Spray and Wait routing scheme. It has been observed that these policies should give preferential treatment to less replicated bundles for a better network performance in terms of delivery ratio and average delivery delay.
Vehicular delay-tolerant networks (VDTNs) appear as an alternative to provide low cost asynchronous internet access on developing countries or isolated regions, enabling non-real time services, such as e-mail, web access, telemedicine, environmental monitoring and other data collection applications. VDTNs are based on the delay-tolerant network (DTN) concept applied to vehicular networks, where vehicles mobility is used for connectivity.
This paper considers a rural connectivity scenario and investigates how different mobility patterns and vehicle densities influence the performance of DTN routing protocols applied to VDTN networks. Moreover, routing protocols parameters are also changed in the present study. We analyse their effect on the performance of VDTNs through the bundle delivery ratio and the bundle average delay.
We expect that this contribution will provide a deep understanding about implications of movement models on the performance of VDTNs applied to rural scenarios, leading to insights for future routing algorithm theoretic study and protocol design.
Based on the concepts of Delay-Tolerant Network (DTN) and Opportunistic Networks, Vehicular opportunistic networks have been proposed to interconnect developing communities, or to implement disaster recovery networks when all other networks fail. Other possible application scenarios for these networks include traffic monitoring, accident warnings, advertisements, and information retrieval applications. The diversity of these network environments introduces challenging issues related to the architecture, protocol designs, interoperability, security, management, and stability of vehicular opportunistic networks. Furthermore, these networks are characterized by variable and intermittent connectivity and frequent network partition. The store-carry-and forward strategy can be used to cope with disconnections. However, in sparse networks with low node density, this strategy may be complemented with the introduction of stationary relay nodes into the network. These nodes are placed along vehicle's routes and create additional transmission opportunities. Therefore, when correctly positioned they will contribute to augment the message delivery ratio. This chapter investigates recent advances related to the deployment of stationary relay nodes on vehicular opportunistic networks. Furthermore, it presents a study that evaluates the impact of adding stationary relay nodes on the performance of DTN routing protocols applied to vehicular opportunistic networks. Two distinct environments were considered, rural and urban scenarios. Each of them combines different application scenarios, map areas, node density, and vehicle movement models. For both scenarios, results show that stationary relay nodes increase the number of contacts between network nodes, improving the overall performance of the network in terms of message delivery ratio.
“Copyright © [2010] IEEE. Reprinted from 15th IEEE International Workshop on Computer-Aided Modeling Analysis and Design of Communication Links and Networks.(IEEE CAMAD 2010) ISBN:978-1-4244-7634-3. 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.”
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O trabalho apresentado no contexto deste artigo pretende contribuir para a construção de uma rede sem fios composta por vários pontos de acesso móveis com a capacidade de se organizarem autonomamente de modo a cobri- rem uma área definida. Nesse sentido, apresenta o desenho, implementação e avaliação de desempenho de um algoritmo que coordena a deslocação autóno- ma de um robô até um nó de destino, com base na avaliação do parâmetro Re- ceived Signal Strength Indication.
This paper assesses the potential for technological modernization and innovation based on Information and Communication Technologies (ICT) in traditional agri‐ food companies located in the central region of Portugal. A survey was applied to 50 agri‐food companies of cereals, cheese, olive oil, dry sausages, honey, wine, and horticultural sectors. Results analysis show that companies use computers, have in‐ ternet service, and use social networks for business purposes. However, most of it have no webpage, do not use internet for advertising/selling/buying products, and have not promoted collaborators’ ICT training. Companies expect webpages to im‐ prove their productivity and/or marketing products/services. Recommendations were provided to promote the use of ICT for business purposes. Webpages, Facebook pages, and CRM systems were developed to a limited set of companies. The results of the satisfaction survey of the ICT solution confirm the company sales increase due to the web visibility gained by the company products.
The use of wireless sensor networks (WSN) can be a valuable contribution in disaster situations or life-threatening exploration. Using wireless mobile robots, it is possible to explore vast areas without human intervention. However, the wireless network coverage that can keep mobile robots connected to the base station / gateway is a major limitation. With this in mind it was created a prototype of an extensible WSN using mobile robot nodes that cooperate amongst themselves. The strategy adopted in this project proposes using three types of nodes: master node, static node, and robot node. Three different algorithms were also developed and proposed: Received Signal Strength Indication (RSSI) Request; Automovement; Robot Cooperation and Response to Static Node. The performance evaluation of the prototype was carried out using a real-world testbed with each developed algorithm. The results achieved were very promising to continue the evolution of the prototype.
The increase of data-rates that are provided by free-space optical (FSO) communications is essential in our data-driven society. When used in satellite and interplanetary networks, these optical links can ensure fast connections, yet they are susceptible to atmospheric disruptions and long orbital delays. The Delay and Disruption Tolerant Networking (DTN) architecture ensures a reliable connection between two end nodes, without the need for a direct connection. This can be an asset when used with FSO links, providing protocols that can handle the intermittent nature of the connection. This paper provides a review on the theoretical and state-of-the-art studies on FSO and DTN. The aim of this review is to provide motivation for the research of an optical wireless satellite network, with focus on the use of the Licklider Transmission Protocol. The assessment presented establishes the viability of these networks, providing many examples to rely on, and summarizing the most recent stage of the development of the technologies addressed.
In a wireless sensor network, energy is almost always the greatest limitation. Energy sources are restricted in many of the environments where nodes are deployed, limiting them to the use of batteries for power. Therefore, conserving energy is supremely important, however, such a task poses many challenges to hardware and protocol design. One of the greatest problems faced is reducing the energy consumption of the communications systems, which represents a substantial amount of the total consumption. This paper surveys the most recent schemes designed to reduce the communications module energy consumption with a focus on novel MAC protocols for ad-hoc wireless sensor networks. It initially describes the many challenges involved, then it analyses each protocol individually. Finally, the presented protocols are compared and the issues that remain open are raised for further research.
“Copyright © [2010] IEEE. Reprinted from 18th International Conference on Software, Telecommunications and Computer Networks (SoftCOM 2010). ISBN: 978-1-4244-8663-2
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Vehicular networks experience a number of unique challenges due to the high mobility of vehicles and highly dynamic network topology, short contact durations, disruption intermittent connectivity, significant loss rates, node density, and frequent network fragmentation. All these issues have a profound impact on routing strategies in these networks. This paper gives an insight about available solutions on related literature for vehicular communications. It overviews and compares the most relevant approaches for data communication in these networks, discussing their influence on routing strategies. It intends to stimulate research and contribute to further advances in this rapidly evolving area where many key open issues that still remain to be addressed are identified.
“Copyright © [2010] IEEE. Reprinted from IEEE International Conference on Communications (IEEE ICC 2010) - General Symposium on Selected Areas in Communications (ICC'10 SAS).ISSN:1550-3607. 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 © [2010] IEEE. Reprinted from IEEE International Conference on Communications (IEEE ICC 2010). ISSN:1550-3607. 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 © [2009] IEEE. Reprinted from International Conference on Parallel Processing Workshops ICPPW '09.ISSN:1530-2016. 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 © 2018 IEEE. Reprinted from 13th Iberian Conference on Information Systems and Technologies (CISTI). ISBN: 978-989-98434-8-6.
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.”
The idea of monitoring several types of parameters in various environments has been motivating significant research works in Internet of Things (IoT). This paper presents the design and construction of iSensA, a system for integrating and collecting information from sensors. The solution implements a multi-sensor monitoring system and then expands the monitoring concept to an IoT solution, by employing multi-network access, Web services, database and web and mobile applications for user interaction. iSensA system is highly configurable, enabling several monitoring solutions with different types of sensors. Experiments have been performed on real application scenarios to validate and evaluate our proposition.
This work is a part of an ongoing study to substitute the identification of waste containers via radio-frequency identification. The purpose of this paper is to propose a method of identification based on computer vision that performs detection using images, video, or real-time video capture to identify different types of waste containers. Compared to the current method of identification, this approach is more agile and does not require as many resources. Two approaches are employed, one using feature detectors/descriptors and other using convolutional neural networks. The former used a vector of locally aggregated descriptors (VLAD); however, it failed to accomplish what was desired. The latter used you only look once (YOLO), a convolutional neural network, and reached an accuracy in the range of 90%, meaning that it correctly identified and classified 90% of the pictures used on the test set.
This paper presents a new approach to help redesigning waste management for the cities of the future. The current state of tracking waste containers is rigid, inefficient and hard to oversee. Although attempts have been made in the past using radio-frequency identification for waste container detection, it has shown problems like flexibility, cost and environmental impact. We propose and demonstrate a solution based on the use of computer vision techniques, for object detection and classification, towards the differentiation between different types of waste containers.
Este artigo apresenta o desenho e implementação de um protótipo fun- cional para avaliar e validar a utilização de técnicas de visão computacional, na identificação de contentores de resíduos no contexto de uma cidade inteligente. Este protótipo recorre à utilização de uma rede neuronal convolucional YOLO e de um microcomputador Jetson Nano da Nvidia. Comparativamente ao método atual de identificação de contentores de resíduos por radiofrequência, esta abor- dagem é mais ágil e diminui os recursos necessários para implementação, contri- buindo para poupar nos gastos logísticos e de implementação da gestão inteli- gente de resíduos.
O trabalho apresentado resulta de uma investigação preliminar que
visa a utilização de técnicas de visão computacional para substituir
o método atual de identificação de contentores de resíduos via
identificação por radiofrequência.
Comparativamente ao método atual, esta abordagem é mais ágil e
diminui os recursos necessários para implementação. A abordagem
aqui discutida é centrada no uso de redes neuronais convolucionais,
mais especificamente a rede YOLO.
The agro-industrial sector consumes a significant amount of natural resources for farming and meat production. By 2050, population growth is expected, generating more demand and, consequently, more consumption of scarce resources. This challenging scenario is a concern of the European Commission, revealed in the Green Deal commitment and by the United Nations’ 12th goal of sustainable development. Thus, organizations must increase productivity and be more sustainable as soon as possible. Internet of Things (IoT) is introduced as a solution to facilitate agro-food companies to be more eco-efficient, mainly facing difficulties on farms, such as food loss and waste, best efficiency in management of resources, and production. The deployment of this technology depends on the stage of maturity and potential of implementation. To assess and characterize companies, with respect of IoT implementation, a survey was applied in 21 micro, small and medium agro-food companies, belonging to milk, honey, olive oil, jams, fruticulture, bakery and pastry, meat, coffee, and wine sectors, in the central region of Portugal. As results, this paper reveals the stage of maturity, level of sophistication, potential, opportunities, solutions, and barriers for implementation of IoT. Additionally, suggestions and recommendations to improve practices are discussed.
Wireless sensor networks are an emerging technology that is used to monitor points or objects of interest in an area. Despite its many applications, this kind of network is often limited by the fact that it is difficult to provide energy to the nodes continuously, forcing the use of batteries, which restricts its operations. Network density may also lead to other problems. Sparse networks require stronger transmissions and have little redundancy while dense networks increase the chances of overhearing and interference. To address these problems, many novel medium access control (MAC) protocols have been developed through the years. The objective of this study is to assess the effectiveness of the T-MAC, B-MAC, and RI-MAC protocols in a variable density network used to collect data inside freight trucks carrying fruits that perish quickly. This article is part of the PrunusPós project, which aims to increase the efficiency of peach and cherry farming in Portugal. The comparison was done using the OMNET++ simulation framework. Our analysis covers the behavior and energetic properties of these protocols as the density of the network increases and shows that RI-MAC is more adaptable and consumes less energy than the alternatives.
Vehicular Delay-Tolerant Network (VDTN) is a new disruptive network architecture where vehicles act as the communication infrastructure. VDTN follows a layered architecture based on control and data planes separation, and positioning the bundle layer under the network layer. VDTN furnishes low-cost asynchronous communications coping with intermittent and sparse connectivity, variable delays and even no end-to-end connection. This paper presents a VDTN prototype (testbed) proposal, which implements and validates the VDTN layered architecture considering the proposed out-of-band signaling. The main goals of the prototype are emulation, demonstration, performance evaluation, and diagnose of protocol stacks and services, proving the applicability of VDTNs over a wide range of environments.
