SHStream: Self-Healing Framework for HTTP Video-Streaming

HTTP video-streaming is leading delivery of video content over the Internet. This phenomenon is explained by the ubiquity of web browsers, the permeability of HTTP traffic and the recent video technologies around HTML5. However, the inclusion of multimedia requests imposes new requirements on web servers due to responses with lifespans that can reach dozens of minutes and timing requirements for data fragments transmitted during the response period. Consequently, web- servers require real-time performance control to avoid playback outages caused by overloading and performance anomalies. We present SHStream , a self-healing framework for web servers delivering video-streaming content that provides (1) load admit- tance to avoid server overloading; (2) prediction of performance anomalies using online data stream learning algorithms; (3) continuous evaluation and selection of the best algorithm for prediction; and (4) proactive recovery by migrating the server to other hosts using container-based virtualization techniques. Evaluation of our framework using several variants of Hoeffding trees and ensemble algorithms showed that with a small number of learning instances, it is possible to achieve approximately 98% of recall and 99% of precision for failure predictions. Additionally, proactive failover can be performed in less than 1 secon

Reboot-based Recovery of Performance Anomalies in Adaptive Bitrate Video-Streaming Services

Performance anomalies represent one common type of failures in Internet servers. Overcoming these failures without introducing server downtimes is of the utmost importance in video-streaming services. These services have large user abandon- ment costs when failures occur after users watch a significant part of a video. Reboot is the most popular and effective technique for overcoming performance anomalies but it takes several minutes from start until the server is warmed-up again to run at its full capacity. During that period, the server is unavailable or provides limited capacity to process end-users’ requests. This paper presents a recovery technique for performance anomalies in HTTP Streaming services, which relies on Container-based Virtualization to implement an efficient multi-phase server reboot technique that minimizes the service downtime. The recovery process includes analysis of variance of request-response times to delimit the server warm-up period, after which the server is running at its full capacity. Experimental results show that the Virtual Container recovery process completes in 72 seconds, which contrasts with the 434 seconds required for full operating system recovery. Both recovery types generate service downtimes imperceptible to end-users

Antecipar para Agir: Potencialidades da Análise Prospetiva para a Construção de “Novos Rumos” do Turismo na Sociedade de Risco

Este artigo tem a finalidade de mostrar como a análise prospetiva constitui uma ferramenta que pode potenciar as dimensões exploratória e estratégica do planeamento em turismo em contextos marcados pela mudança acelerada, o risco e outras incertezas e, nessa medida, auxiliar atores e stakeholders nos processos de definição e construção de novos rumos para o turismo. Os estudos prospetivos são hoje uma poderosa ferramenta na área do planeamento e assumem maior pertinência em tempos incertos, balizados pela complexidade e por inúmeros constrangimentos (mas também oportunidades) associados à globalização e à(s) crise(s) que afetam o sistema-mundo. No domínio do Turismo, como noutros, além de informar as políticas, através dos diagnósticos prospetivos que realiza, a análise prospetiva pode potenciar a construção de redes de atores envolvidos na «modelação do futuro» na área da inovação social e, ainda, contribuir para desenvolver capacidades em toda a região no domínio do desenvolvimento de uma “cultura prospetiva”, reforçando o empowerment coletivo e as suas próprias redes. Em síntese, o conhecimento de métodos, técnicas e formas de operacionalização da prospetiva por parte dos atores individuais e coletivos do setor turístico podem ser uma mais-valia diferenciadora e potenciadora de um planeamento estratégico mais informado, participado e partilhado

Ânforas da Villa Romana de Vilares de Alfundão (Ferreira do Alentejo)

Os autores estudam um conjunto anfórico recolhido nos restos conservados à superfície de uma villa romana, Vilares de Alfundão (Ferreira do Alentejo). Da análise tipológica e do estudo das pastas cerâmicas, conclui-se que a maioria terá sido fabricada nos fornos do Baixo Sado, predominando largamente as formas Dressel 14b e Almagro 51c. Tais resultados são comparados e discutidos, especialmente com os obtidos do estudo das ânforas de S. Cucufate (Vidigueira). Em dois fundos de ânforas DresseI 14 aparece o mesmo grafito e um dos exemplares da forma Almagro 50 ostenta na asa a marca [ . .. ] CVRVCVNIN

An integrated investigation of the Rio tailings, Panasqueira mine, Centre Portugal

The risks associated with mine tailings have different nature and, thus, only a multiple approach can investigate and monitor comprehensively the characteristics and evolution of mine tailings impacts on the environment. Deposition at the Rio tailings (Panasqueira Mine) lasted about ninety years. Over one million cubic metres, of complex very fine to fine material, are deposited on a mountain side overlaying the Zezere river, increasing the risk of contamination of one of the most important hydrographic basins in central Portugal. Herein, a multidisciplinary study including geophysics, geochemistry and borehole information, organized in a GIS, is used to characterize the Rio tailings. The geophysical survey comprised ERT (Electrical Resistivity Tomography) and GPR (Ground Penetrating Radar) on the mud impoundment, as well as, on the slope of the tailings. The geochemical survey consisted on collecting water and tailings samples, iron coatings, arsenopyrite stockpile material and ferruginous crust. Samples collected in boreholes, drilled specifically for this project, were also analyzed. The GIS provided imaging of the geophysical, geochemical and particle size spatial distribution, so that comparisons between the different data sets are easily done. Resistivity and GPR allowed bedrock positioning. GPR was able to give layering results within the tailings. Finally, comparison and correlation between geophysical and geochemical results are carried out and evaluated on the GIS platform

Production and characterization of mead from the honey of Melipona scutellaris stingless bees

The Institute of Brewing & Distilling Mead is a traditional alcoholic beverage obtained by fermenting must and can offer a solution to honey over-production and a way of valorizing honey of lower quality. The purpose of this study was to produce and characterize mead with different levels of sugars and alcohol obtained from honey from Melipona scutellaris. The honey used for mead preparation was analysed in order to ensure that it met the required quality standards. It was found that the alcoholic content and volatile acidity were outwith the limits established by Brazilian law. Mead legislation is based on the product obtained from Apis mellifera (‘honey bee’) honey and these results indicate the need to re-evaluate the standards established for this product in order to incorporate mead produced from honey from stingless bees of the genus Melipona. Copyright © 2018 The Institute of Brewing & Distilling.We thank the Coordination for the Improvement of Higher Education Personnel (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for granting a scholarship of the Institutional Program of Scholarships of Doctorate Sandwich Abroad to Samira Maria Peixoto Cavalcante da Silva, financial support for the project and a scholarship granted to Leticia M. Estevinho. We also thank the National Council for Scientific and Technological Development (Conselho Nacional de Desenvolvimento Científico e Tecnológico) for a research scholarship granted to Carlos Alfredo Lopes de Carvalho. We thank the Polytechnic Institute of Bragança, in particular to the Laboratory of Microbiology, for the development of the work. This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT IP and by the ERDF through the COMPETE2020 – Programa Operacional Competitividade e Internacionalização.info:eu-repo/semantics/publishedVersio

Osteoporosis management during the COVID-19 pandemic - Position paper

verCOVID-19 pandemic significantly increased the already large number of victims of osteoporosis in Portugal. Osteoporosis outpatient clinics were either closed or had limited presential appointments. Many hospitals reduced orthopaedic services to make space for patients with COVID-19. In addition, the volunteer or forced sedentarism, as imposed by the pandemic, increased the risk of falls and fractures drastically. It urges to intensify the current efforts to improve the management of bone health and to prioritize fragility fracture care and prevention. This paper addresses the challenges in osteoporosis management during the COVID-19 pandemic and provides guidance on osteoporosis management. This position paper is a joint initiative of several health professionals and patients dedicated to osteoporosis.publishersversionpublishe