Evaluación del rendimiento del servicio de videostreaming adaptativo en redes inalámbricas

YouTube Live is one of the most popular services on the Internet, enabling an easy streaming of a live video with acceptable video quality. Thus, understanding user´s perception of this service is of the utmost importance for network operators. The image Quality delivered and user videoplayback behavior on YouTube Live streaming are important keys to ensure an adequate Quality of Experience (QoE). In this paper, an analytical model, and stacked Bar Graph to estimate the QoE for encrypted YouTube Live service from packet-level data collected in the interfaces of a wireless network is presented. The inputs to the model are Transport Control Protocol (TCP)/Internet Protocol (IP) metrics, from which two Service Key Performance Indicators (S-KPIs) are estimated, namely video quality level (itag) and, videoplayback connection ratio. The model is developed with an experimental platform, consisting of a user terminal agent, a WiFi wireless network, a network-level emulator, a Mitmproxy and a probe software. Model assessment is carried out by comparing S-KPI estimates with measurements from the terminal agent under different network conditions introduced by the network emulator.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Ministerio de Economía y Competitividad (Proyecto TEC2015-69982-R, UNMA13-1E-1864), y FEDER

A Value-Based Approach for Reasoning with Goal Models

Goal models are used to represent stakeholders’ intentions regarding the system to be developed and the alternative means to achieve those intentions. Goal-oriented analysis techniques have been proposed to help analysts reason when employing goal models. These techniques can be used to identify conflicts among goals, to choose between alternatives or to check the satisfiability of the model. Unfortunately, most of these techniques consider that stakeholders their intentions are equally important. This paper presents a value-based approach that and allows stakeholders to assign a relative importance to the elements in a goal model. It then propagates that importance by means of their relationships (dependencies, contributions and decompositions) in order to determine which elements are more valuable. Fisher’s weighted distribution and multi-criteria decision analysis techniques are used to deal with the propagation of the importance among the goals. The contribution is the alignment of information system with stakeholders and organizational goals

A quality of experience evaluation method for an UAV first person view system

Unmanned Aerial Vehicles (UAV) communication systems are an increasingly widespread and emerging technology due to their flexibility, low cost and usability properties. Hence, the demand for Beyond Visual Line of Sight (BVLOS) cases that require large data transmission and low latency in cellular networks are increasingly. In this work, the assembly, integration and networking of a UAV quadrotor for First Person View (FPV) system connected by LTE is presented. Different configurations of the link between the UAV and the Ground Control Station (GCS) are proposed, such as connection by LTE cloud-based server, direct LTE connection and direct WiFi connection. With these configurations, experiments are carried out to characterise the network metrics that model this service according to the telemetry, control and video traffic. The main contribution is the definition of a closed mathematical expression provided to define the Quality of Experience (QoE) for FPV use cases considering the video quality in terms of Video Multimethod Assessment Fusion (VMAF), network latency and video resolution as inputs. This expression will be applied to lab experiments taking into account link performance, in which network changes based in packet loss and latency alterations will be introduced to measure the QoE of the UAV system.Campus de Excelencia Internacional Andalucía Tech

Comparación de servicios de video streaming de YouTube

YouTube is one of the most popular services on the Internet, enabling easy streaming of a video (conventional or live) with acceptable video quality. In March 2015, YouTube added 360o video streaming service which provides users with panoramic view and allows them to freely control their viewing direction during video playback. At present, the most important service in mobile networks is video streaming, which is expected to generate 82% of all IP traffic volume by 2021. Thus, understanding YouTube video and its features is the utmost importance for network operators. In this paper, a comparative study to identify the differences between the conventional and live YouTube streaming service is presented, which includes the 360o video. The analysis covers both protocol messages and application behavior. To that end, different combinations of client type (mobile phone or PC) and video service type (conventional or live) are tested. For each combination, a short video streaming session is established, where all HTTP messages (request/response) are captured and decrypted between the YouTube client and server in the video playback sequence.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Impacto enlace ascendente YouTube 360° Live Video Streaming

At present, the most important service in mobile networks is video streaming, which is expected to generate 82% of all IP traffic volume by 2021. YouTube is one of the most popular video services on the Internet. In March 2015, YouTube added 360º video streaming service, which provides users with panoramic view and allows them to freely control their viewing direction during video playback. It is getting popular due to the recent availability of commercial devices that support 360 video interactivity as smartphones/tablets and head-mounted displays. 360° live video streaming is very challenging due to high bandwidth requirements. To address this problem, the video quality is adjusted according to the user viewport prediction. High-quality video is only streamed for the user viewport while the rest of the frame is transmitted in lower quality, reducing the overall bandwidth consumption, but this solution is not sufficient for the high requirements demanded by users. Thus, the optimization of this service is the utmost importance for network operators. In this paper, a study of the uplink in the broadcast video live section and its impact on the quality of experience perceived by the end-user is presented. The results show video quality, end-to-end latency and MOS (Mean Opinion Score). The analysis has been carried out by collecting traces at network level for TCP/IP metrics, HTTP messages by HAR traces every 300 s for video segment quality and end to end latency and user-level traces of each live 360 ° video session for S-KPIs (Service Key Performance Indicators).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Este trabajo ha sido financiado por el Ministerio de Ciencia, Innovaci´on y Universidades (Proyecto TEC2015-69982-R y RTI2018-099148-B-I00)

Specifying Value in GRL for Guiding BPMN Activities Prioritization

In a value-based requirements engineering approach, the stakeholders’ value propositions must be considered ahead in order to prioritize which requirements will be developed first to drive the software development activities. Early requirements approaches like the Goal- Oriented Requirements Language (GRL) focuses on modeling goals, tasks, contributions, and dependencies in order to satisfy the stakeholders’ needs, but do not provide a mechanism to specify value according to stakeholders’ value propositions. Moreover, in software development, after specifying value propositions, there is a need to align goal elements into business process elements in order to prioritize which business process activity is going to be developed next. Thus, we propose a new approach (value@GRL) to improve GRL and prioritize Business Process Model and Notation (BPMN) activities. Value@GRL provides guidelines for specifying value in GRL models according to the stakeholders’ needs and prioritization mechanisms to define BPMN activities\u27 order in an incremental software development

Análisis del impacto de las tecnologías web en el rendimiento del servicio de navegación web

Ministerio de Ciencia e Innovación (RTI2018-099148-B-I00), la Agencia Estatal de Investigación (FPI/BES-2016-07631) y la Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.Las propiedades de una página web tienen un fuerte impacto en la experiencia de los usuarios de la web. En este trabajo se propone un método de clasificación basado en la agrupación no supervisada para páginas web en clases, basadas en el contenido de las descargas puede afectar la calidad de la experiencia (QoE) percibida por el usuario y su caracterización a través del conjunto de tecnologías web que utilizan. Los grupos se definen basándose en el estándar Multipurpose Internet Mail Extensions (MIME) estándar y conexiones de subdominios externos, obtenidas a través de en el navegador y a nivel de aplicación en 500 sitios web populares. Los datos recogidos se dividen en grupos con un algoritmo clásico de aprendizaje no supervisado denominado K-means. Por último, los grupos se caracterizan según el conjunto de tecnologías web utilizadas. Los resultados muestran la clasificación de las páginas web en seis grupos y sus características de agrupación y cómo JQuery (el JavaScript más popular) influye en el tiempo de carga de las páginas web. JavaScript) influye en el tiempo de carga de las páginas web.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Modelo de evaluación de calidad de experiencia para servicios de vídeo inmersivo por LTE basado en drones

Several upcoming 5G and 6G services rely on Unmanned Aerial Vehicles (UAV) sending live data to other remote User Equipments (UEs) in Beyond Visual Line of Sight (BVLOS) scenarios. Thus, understanding the traffic flows implied in these services and estimating Quality of Experience (QoE) perceived by end-users is key for network operators. One of these services is First Person View (FPV), consisting on the remote control of the UAV by the live video visualised in the Ground Control Station (GCS). In this work, an UAV quadrotor for FPV system connected by LTE is presented. The main contribution is the definition of a closed mathematical expression provided to define the Quality of Experience (QoE) for FPV use cases considering the video quality in terms of Video Multimethod Assessment Fusion (VMAF), network latency and video resolution as inputs. This expression will be applied to lab experiments taking into account link performance, in which network changes based on packet loss, throttling and latency alterations will be introduced to measure the QoE of the UAV system.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Medida y análisis del tráfico para el control inmersivo de Drones.

Los vehículos aéreos no tripulados (UAV) han experimentado un creciente desarrollo como factores clave de nuevas aplicaciones en la actualidad, como los servicios vigilancia, control y rescate, la agricultura, la gestión de catástrofes o incluso en actividades de ocio. Este artículo aborda la conexión del dron por LTE para las aplicaciones de visión en primera persona (FPV), para las que se necesita una comunicación de baja latencia para lograr una calidad de servicio (QoS) adecuada. En primer lugar, se ha detallado el sistema del dron y la plataforma de control considerada para realizar las pruebas. Tras ello, se muestra un estudio comparativo de las métricas de rendimiento de la red de tamaño de los paquetes, el tiempo entre ellos y la tasa binaria para el sistema con una configuración de conexión LTE por medio de un servidor en la nube, con respecto a un enlace punto a punto. Además, se presenta gráficamente los resultados de latencia de la red en los diferentes enlaces de comunicación, obteniendo mejores prestaciones con enlaces punto a punto.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Spatiotemporal use predicts social partitioning of bottlenose dolphins with strong home range overlap

© 2018 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Ranging behaviour and temporal patterns of individuals are known to be fundamental sources of variation in social networks. Spatiotemporal dynamics can both provide and inhibit opportunities for individuals to associate, and should therefore be considered in social analysis. This study investigated the social structure of a Lahille's bottlenose dolphin (Tursiops truncatus gephyreus) population, which shows different spatiotemporal patterns of use and gregariousness between individuals. For this, we constructed an initial social network using association indices corrected for gregariousness and then uncovered affiliations from this social network using generalized affiliation indices. The association‐based social network strongly supported that this dolphin population consists of four social units highly correlated to spatiotemporal use patterns. Excluding the effects of gregariousness and spatiotemporal patterns, the affiliation‐based social network suggested an additional two social units. Although the affiliation‐based social units shared a large part of their core areas, space and/or time use by individuals of the different units were generally distinct. Four of the units were strongly associated with both estuarine and shallow coastal areas, while the other two units were restricted to shallow coastal waters to the south (SC) and north of the estuary (NC), respectively. Interactions between individuals of different social units also occurred, but dolphins from the NC were relatively more isolated and mainly connected to SC dolphins. From a conservation management perspective, it is recommended that information about the dolphin social units should be incorporated in modeling intrapopulation dynamics and viability, as well as for investigating patterns of gene flow among them