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Network Fortune Cookie: Using Network Measurements to Predict Video Streaming Performance and QoE

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... Esses trabalhos avaliam o impacto de métricas de desempenho-como banda de rede, taxa de perdas de pacote e taxa de transmissão-no desempenho de aplicações específicas, incluindo vídeo [Casas et al. 2013, Gill et al. 2007, Shafiq et al. 2014, Chen et al. 2015, Ahmed et al. 2017. Entretanto, previsões, quando realizadas, são direcionadas a descoberta da opinião subjetiva dos usuários a respeito da qualidade de experiência (Mean Opinion Score, MOS) a partir das métricas de desempenho [da Costa Filho et al. 2016, Balachandran et al. 2013. Isso se deveà existência de diversos obstáculosà predição de engajamento. ...
... Tipicamente, os métodos existentes usam a taxa do vídeo ou estatísticas globais de eventos de stalls como previsores de QoE. Por exemplo, [da Costa Filho et al. 2016] estimam QoE através de umaárvore de decisão, tomando como variáveis independentes métricas de desempenho obtidas em um ambiente controlado. Essa abordagem não leva em conta transmissões adaptativas. ...
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Os recentes esforços no desenvolvimento de algoritmos de adaptação e alocação de usuários têm contribuído de forma significativa para o aumento da qualidade de experiência (QoE) na distribuição de vídeo ao vivo na Internet. Entretanto, uma considerável parcela de sessões ainda sofre com baixa QoE, o que pode implicar em queda de engajamento dos usuários. Esse problema persiste uma vez que os provedores de serviço não conseguem prever a sáıda de um usuário e tomar medidas para evitá-la. Neste trabalho, propomos um modelo multi-estágio para predição de engajamento baseado em variáveis historicamente relacionadas a QoE. As sessões são agrupadas de acordo com suas similaridades de desempenho. Para cada grupo de sessões, modelos baseados emárvores de decisão são criados para prever (1) o tempo restante da sessão e (2) se o usuário permanecerá ou não no sistema pelos próximos n minutos. Experimentos com um conjunto de dados reais mostram uma significativa acurácia na predição de tempo restante e permanência, o que evidencia a viabilidade do uso das métricas de desempenho para prever engajamento de usuários.
... Many methods rely on Deep Packet Inspection (DPI), which is becoming infeasible due to the adoption of encryption protocols, on top of raising privacy issues [15], [16]. Other methods monitor the high-level network performance and use statistical models to map the objective metrics into indicators of user experience [17]. One problem commonly found on existing methods is how to cover the last mile of the end-to-end connection between server and client, since network monitoring tools usually require agents to be installed on the device to perform measurements. ...
... Um problema comum na Internet é o congestionamento, devido à redução de largura de banda ou presença de múltiplos usuários [Jiang, Sekar, and Zhang 2014], [Da Costa et al. 2016]. Para minimizá-lo, os mecanismos de controle de congestionamento para TCP são implementados [Cai, Shen, Pan, and Mark 2005]. ...
... Nela os usuários dão notas a aspectos relacionadosà qualidade do vídeo assistido. MOSé usada, por exemplo, por [da Costa Filho et al. 2016], que propõe um previsor para estimar o impacto de diversas métricas de qualidade de serviço (QoS) no valor de MOS. Apesar de confiável, a métrica MOS nãoé escalável, visto que a obtenção de um conjunto de referência representativo requer contribuição de uma grande parcela de usuários, o que nem sempreé trivial. ...
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Today, video streaming is a well-established application on the internet. Providers are capable of transmitting video globally, in large-scale, although there are still some challenges, such as offering high quality of experience (QoE) for all clients. To face this problem, the content providers try to predict low QoE based on historical system performance to prevent the occurrence of new cases of low quality. In other words, the provider monitors the session performance (the average bitrate and rebuffering rate, for example) and applies methods to correlate this to a metric that expresses QoE, such as user engagement. This method allows the detection of the aspects that contribute to early session abandonment. However, the success of this approach depends on the accuracy of the QoE prediction: past works report an accuracy up to 70% using the pre-mentioned correlation between performance and engagement. In this work, we propose a new method for engagement prediction through the use of the client adaptation regime in replacement of the pre-mentioned performance metrics. We show that this new approach is capable of achieving 81% of prediction accuracy. We also present a case study for the CDN control plan that uses QoE prediction. We found that its use can lead to potential gains in user engagement in comparison to the default provider approach. Resumo. As transmissões de vídeo ao vivo já romperam a fronteira da escala global e agora enfrentam um novo desafio: oferecer alta qualidade de experiência (QoE) de maneira uniforme. Para atacar esse problema, diversas abordagens utilizam informações históricas relacionadas ao desempenho de transmissão para inferir a qualidade de experiência (QoE) de suas sessões. Prever a QoE de maneira acurada permite que provedores de serviço, proativamente, estimem e aloquem recursos a cada um de seus clientes. No entanto, o sucesso dessa alocação de recursos customizada depende de uma previsão acurada de QoE: tipicamente, a previsãoé feita por meio de métricas de desempenho como taxa de interrupções e bitrate médio e alcançam uma acurácia abaixo de 70%. Neste trabalho, apresentamos uma nova abordagem, que correlaciona a QoE do cliente com o perfil de adaptação da sua mídia. Nós mostramos que o novo conjunto de métricas proposto aumenta a acurácia de previsão para 81%. Também apresentamos um estudo de caso para alocação de clientes usando o previsor e demonstramos que existe um potencial de duplicação da QoE geral se comparadoà alocação padrão empregada pelo provedor.
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