Service Migration from Cloud to Multi-tier Fog Nodes for Multimedia Dissemination with QoE Support.

A wide range of multimedia services is expected to be offered for mobile users via various wireless access networks. Even the integration of Cloud Computing in such networks does not support an adequate Quality of Experience (QoE) in areas with high demands for multimedia contents. Fog computing has been conceptualized to facilitate the deployment of new services that cloud computing cannot provide, particularly those demanding QoE guarantees. These services are provided using fog nodes located at the network edge, which is capable of virtualizing their functions/applications. Service migration from the cloud to fog nodes can be actuated by request patterns and the timing issues. To the best of our knowledge, existing works on fog computing focus on architecture and fog node deployment issues. In this article, we describe the operational impacts and benefits associated with service migration from the cloud to multi-tier fog computing for video distribution with QoE support. Besides that, we perform the evaluation of such service migration of video services. Finally, we present potential research challenges and trends

Uma Plataforma experimental para avaliação de desempenho de estimadores de qualidade de enlace em rede de sensores sem fio

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pòs-graduação em Engenharia de Automação e Sistemas, Florianópolis, 2010A realização de experimentos reais em Redes de Sensores Sem Fio (RSSF) permite aos pesquisadores obterem resultados mais precisos se comparado com simulações. Isto pode ser aplicado, por exemplo, para entender e avaliar novos protocolos MAC, algoritmos de roteamento e também estimadores de qualidade de enlace. Contudo, a experimentação real exige o uso de ferramenta computacional apropriada, chamada de testbed. Por esta razão, nesta dissertação propomos um novo testbed para realizar experimentos em RSSF para avaliar estimadores de qualidade de enlace. Nosso testbed é constituído por: (i) componentes de hardware disponíveis no mercado para realizar experimentos e coletar dados; (ii) uma ferramenta de software para controlar e analisar os experimentos. Apresentamos um estudo de caso do testbed para realizar a avaliação de desempenho de diferentes estimadores de qualidade de enlace. Os resultados coletados foram de fundamental importância para criação de um novo estimador de qualidade de enlace no contexto de um trabalho relacionado

Federated User Clustering for non-IID Federated Learning

Federated Learning (FL) is one of the leading learning paradigms for enabling a more significant presence of intelligent applications in networking considering highly distributed environments while preserving user privacy.However, FL has the significant shortcoming of requiring user data to be Independent Identically Distributed (IID) to make reliable predictions for a given group of users.We present a Neural Network-based Federated Clustering mechanism capable of clustering the local models trained by users of the network with no access to their raw data.We also present an alternative to the FedAvg aggregation algorithm used in traditional FL, which significantly increases the aggregated models' reliability in Mean Square Error by creating several training models over IID users

GEOGRAFIA E AS REPRESENTAÇÕES DOS LUGARES SAGRADOS: UMA ANÁLISE DE PALMEIRA-PR

This research concerns to the submitted project to the Scientific Initiation Program of the Midwest State University (UNICENTRO) in 2015. Its main goal was to seek the theoretical propositions that aim to give prominence to the interpretation of socio-spatial phenomena, that is, to understand the representations of the sacred contextualized in the geographical imagination in the city of Palmeira, State of Paraná. For a better analysis and understanding, we seek to understand the practices and uses of the “Bom Jesus do Monte“, better known as “Capelinhas de Vieiras”. This place is located in the community of Vieiras in the countryside of the county, in this area are built 14 chapels in cruse form, which represent the devotion of a Portuguese immigrant by the deities who attended him when requested. After the bibliographical analysis, informal interviews were conducted with people from the community of Vieiras, as well as questionnaires in the printed form were applied about the uses and utility of the place. Through the results obtained we come to some considerations and proposals, made at the end of this article.A presente pesquisa trata-se de um projeto submetido ao programa de Iniciação Cientifica da Universidade Estadual do Centro-Oeste (UNICENTRO) no ano de 2015. Teve como objetivo principal buscar as proposições teóricas que almejam dar relevo à interpretação dos fenômenos sócio-espaciais, ou seja, compreender as representações do sagrado contextualizando na seara da imaginação geográfica na cidade Palmeira no Paraná. Para uma melhor analise e compreensão, buscamos entender as práticas e usos do “Santuário Bom Jejus do Monte”, mais conhecido como “Capelinhas de Vieiras”. Este espaço está situado na comunidade de Vieiras na zona rural do município, neste local estão edificadas 14 capelas em forma de cruzeiro, que representam a devoção de um imigrante português pelas divindades que lhe atenderam quando solicitado. Após a análise bibliográfica, foram feitas entrevistas informais com pessoas da comunidade de Vieiras, bem como questionários na forma impressa onde foram perguntadas questões de uso e utilidade do local. Através dos resultados obtidos chegamos a algumas considerações e propostas, feitas ao final deste artigo

Skipping-based handover algorithm for video distribution over ultra-dense VANET

Next-generation networks will pave the way for video distribution over vehicular Networks (VANETs), which will be composed of ultra-dense heterogeneous radio networks by considering existing communication infrastructures to achieve higher spectral efficiency and spectrum reuse rates. However, the increased number of cells makes mobility management schemes a challenging task for 5G VANET, since vehicles frequently switch among different networks, leading to unnecessary handovers, higher overhead, and ping-pong effect. In this sense, an inefficient handover algorithm delivers videos with poor Quality of Experience (QoE), caused by frequent and ping-pong handover that leads to high packets/video frames losses. In this article, we introduce a multi-criteria skipping-based handover algorithm for video distribution over ultra-dense 5G VANET, called Skip-HoVe. It considers a skipping mechanism coupled with mobility prediction, Quality of Service (QoS)- and QoE-aware decision, meaning the handovers are made more reliable and less frequently. Simulation results show the efficiency of Skip-HoVe to deliver videos with Mean Opinion Score (MOS) 30% better compared to state-of-the-art algorithms while maintaining a ping-pong rate around 2%.publishe

Demo abstract: RadiaLE: a framework for benchmarking link quality estimators

Link quality estimation is a fundamental building block for the design of several different mechanisms and protocols in wireless sensor networks (WSN). A thorough experimental evaluation of link quality estimators (LQEs) is thus mandatory. Several WSN experimental testbeds have been designed ([1–4]) but only [3] and [2] targeted link quality measurements. However, these were exploited for analyzing low-power links characteristics rather than the performance of LQEs. Despite its importance, the experimental performance evaluation of LQEs remains an open problem, mainly due to the difficulty to provide a quantitative evaluation of their accuracy. This motivated us to build a benchmarking testbed for LQE - RadiaLE, which we present here as a demo. It includes (i.) hardware components that represent the WSN under test and (ii.) a software tool for the set up and control of the experiments and also for analyzing the collected data, allowing for LQEs evaluation

A Survey on Long-Range Wide-Area Network Technology Optimizations

Long-Range Wide-Area Network (LoRaWAN) enables flexible long-range service communications with low power consumption which is suitable for many IoT applications. The densification of LoRaWAN, which is needed to meet a wide range of IoT networking requirements, poses further challenges. For instance, the deployment of gateways and IoT devices are widely deployed in urban areas, which leads to interference caused by concurrent transmissions on the same channel. In this context, it is crucial to understand aspects such as the coexistence of IoT devices and applications, resource allocation, Media Access Control (MAC) layer, network planning, and mobility support, that directly affect LoRaWAN’s performance.We present a systematic review of state-of-the-art works for LoRaWAN optimization solutions for IoT networking operations. We focus on five aspects that directly affect the performance of LoRaWAN. These specific aspects are directly associated with the challenges of densification of LoRaWAN. Based on the literature analysis, we present a taxonomy covering five aspects related to LoRaWAN optimizations for efficient IoT networks. Finally, we identify key research challenges and open issues in LoRaWAN optimizations for IoT networking operations that must be further studied in the future

STFANET : SDN-Based Topology Management for Flying Ad Hoc Network

In recent years, with the growth in the use of Unmanned Aerial Vehicles (UAVs), UAV-based systems have become popular in both military and civil applications. The lack of reliable communication infrastructure in these scenarios has motivated the use of UAVs to establish a network as flying nodes, also known as Flying Ad Hoc Networks (FANETs). However, the high mobility degree of flying and terrestrial users may be responsible for constant changes in the network topology, which makes more challenging to guarantee their communication during the operational time. In this context, this article presents a Software-defined networking (SDN) based Topology management for FANETs - called of STFANET -, which is a coordination protocol that englobes both an efficient SDN-based UAV communication and a set of topology management algorithms. The goal is to establish and maintain a FANET topology in order to provide a constant and reliable communication link among independent nodes - which are performing individual or collaborative missions - through relays units. Simulation results show the efficiency of the proposed protocol in order to provide communication in a dynamic scenario. Considering its use in a military setting, STFANET managed to achieve 25% of packet loss in transmitting data packets, 1.5ms of latency and 71% of connectivity on average

The Basic Education Teacher and the Digital Technologies in Emergency Remote Teaching.

Este artigo se propõe a analisar a percepção de professores da Educação Básica sobre as suas práticas e o ensino remoto, implantado de forma emergencial devido à pandemia da Covid-19. Trata-se de um levantamento, do qual participaram 46 professores que responderam um formulário com 17 perguntas fechadas e uma aberta sobre essa experiência, as tecnologias digitais utilizadas, as dificuldades nessa implementação, o acesso a internet, entre outros. As participantes identificaram os aplicativos de mensagem (WhatsApp e Telegram) como as ferramentas mais utilizadas nas aulas, sendo consideradas as mais fáceis. Observou-se neles a postura de permanentes aprendizes.This article aims to analyze the perception of elementary school teachers about their practices and remote teaching, which was implemented in an emergency due to the Covid-19 pandemic. It is a survey, in which 46 teach-ers participated when answering a form with 17 closed questions and an open one about this experience, the digital technologies used, the difficul-ties in this implementation, the access to the internet, among others. The participants identified messaging applications (WhatsApp and Telegram) as the most used tools in class, being considered the easiest, and the posture of permanent learners was observed in them