Now showing 1 - 6 of 6
  • Publication
    How Crisp is the Crease? A Subjective Study on Web Browsing Perception of Above-The-Fold
    Quality of Experience (QoE) for various types of websites has gained significant attention in recent years. In order to design and evaluate websites, a metric that can estimate a user’s experienced quality robustly for diverse content is necessary. SpeedIndex (SI) has been widely adopted to estimate perceived web page loading progress. It measures the speed of rendering pixels for the webpage that is visible in the browser window. This is termed Above-The-Fold (ATF). The influence of animated content on the perception of ATF has been less comprehensively explored. In this paper, we present an experimental design and methodology to measure ATF perceptionfor websites with and without animated elements for various pagecontent categories. We found that pages with animated elements caused people to have more varied perceptions of ATF under different network conditions. Animated content also impacts the page load estimation accuracy of SI for websites. We discuss how the difference in the perception of ATF will impact the QoE management of web applications. We explain the necessity of revisiting the visual assessment of ATF to include the animated contents and improve the robustness of metrics like SI.
      307Scopus© Citations 6
  • Publication
    Fusion confusion: Exploring ambisonic spatial localisation for audio-visual immersion using the McGurk effect
    Virtual Reality (VR) is attracting the attention of application developers for purposes beyond entertainment including serious games, health, education and training. By including 3D audio the overall VR quality of experience (QoE) will be enhanced through greater immersion. Better understanding the perception of spatial audio localisation in audio-visual immersion is needed especially in streaming applications where bandwidth is limited and compression is required. This paper explores the impact of audio-visual fusion on speech due to mismatches in a perceived talker location and the corresponding sound using a phenomenon known as the McGurk effect and binaurally rendered Ambisonic spatial audio. The illusion of the McGurk effect happens when a sound of a syllable paired with a video of a second syllable, gives the perception of a third syllable. For instance the sound of /ba/ dubbed in video of /ga/ will lead to the illusion of hearing /da/. Several studies investigated factors involved in the McGurk effect, but a little has been done to understand the audio spatial effect on this illusion. 3D spatial audio generated with Ambisonics has been shown to provide satisfactory QoE with respect to localisation of sound sources which makes it suitable for VR applications but not for audio visual talker scenarios. In order to test the perception of the McGurk effect at different direction of arrival (DOA) of sound, we rendered Ambisonics signals at the azimuth of 0°, 30°, 60°, and 90° to both the left and right of the video source. The results show that the audio visual fusion significantly affects the perception of the speech. Yet the spatial audio does not significantly impact the illusion. This finding suggests that precise localisation of speech audio might not be as critical for speech intelligibility. It was found that a more significant factor was the intelligibility of speech itself.
      469Scopus© Citations 6
  • Publication
    Beyond First Impressions: Estimating Quality of Experience for Interactive Web Applications
    The number of web applications for both personal and business use will continue to increase. The popularity of web applications has grown, increasing the need to estimate Quality of Experience for web applications (Web QoE). Web QoE helps providers to understand how their end-users perceive quality and point towards areas to improve. Waiting time has been proven to have a significant influence on user satisfaction. Most studies in the field of Web QoE have focused on modelling Web QoE for the user’s first interaction with the application, e.g., the waiting time for the first page load to complete. This does not include a user’s subsequent interactions with the application. Users keep interacting with the application beyond the first page load resulting in an experience that consists of a series of waiting times. In this study, we have chosen web maps as a use case to investigate how to measure waiting time for a user’s interactions across a web browsing session, and to measure the correlation between waiting time and user-reported perceived quality. We provide a short survey of existing Web QoE estimation metrics and models. We then propose two new measures: interactive Load Time (iLT) and Total Completed interactive Load (TCiL) to establish the waiting time associated with a web application user’s interactions. A subjective study confirms a logarithmic relationship for interactive web application sessions between iLT and perceived quality. We compare the correlation between QoE for iLT and the state of the art, non-interactive equivalent, Page Load Time (PLT)/Waiting Time. We demonstrate how the iLT/QoE fitting curve deviates from PLT/QoE. The number of clicks in completing tasks and TCiL are explored to explain the connections between user’s interactions behaviour and the perceived quality.
      331Scopus© Citations 18
  • Publication
    You Drive Me Crazy! Interactive QoE Assessment for Telepresence Robot Control
    Telepresence robots (TPRs) are versatile, remotely controlled vehicles that enable physical presence and human-to-human interaction over a distance. Thanks to improving hardware and dropping price points, TPRs enjoy the growing interest in various industries and application domains. Still, a satisfying experience remains key for their acceptance and successful adoption, not only in terms of enabling remote communication with others, but also in terms of managing robot mobility by means of remote navigation. This paper focuses on the latter aspect of remote operation which has been hitherto neglected. We present the results of an extensive subjective study designed to systematically assess remote navigation Quality of Experience (QoE) in the context of using a TPR live over the Internet. Participants were ‘beamed’ into a remote office space and asked to perform characteristic TPR remote operation tasks (driving, turning, parking). Visual and control dimensions of their experience were systematically impaired by altering network characteristics (bandwidth, delay and packet loss rate) in a controlled fashion. Our results show that users can differentiate well between visual and navigation/control aspects of their experience. Furthermore, QoE impairment sensitivity varies with the actual task at hand.
      339Scopus© Citations 7
  • Publication
    Establishing Waiting Time Thresholds in Interactive Web Mapping Applications for Network QoE Management
    Customer expectations will continue to drive communication service developers to optimise their use of network resources based on user satisfaction. Thus, network platforms need to be remodelled from Quality of Service (QoS) centric to Quality of Experience (QoE) aware platforms. The perceived QoE for interactive web applications such as Google maps or Openstreetmaps is dominated by waiting time, i.e. the perceived time to render the page and map. Studies have explored waiting time estimation for Web QoE applications (e.g. email, downloads, web pages). Perceived waiting time for web mapping applications have been less comprehensively explored. The relationship between perceived waiting time and network QoS is a key QoE management factor to enable QoE aware networks. In this paper, we review the principle of network QoE management and the perception of waiting times. We present experimental design and methodology that facilitate the identification of waiting time thresholds for web applications, using web maps as a use case. We outline our results along with a statistical analysis and discussion interpreting the results and their applications. Finally, we discuss follow-up experiments and how they could be developed and applied in the network QoE management.
      238Scopus© Citations 6
  • Publication
    Towards Application-Aware Networking: ML-Based End-to-End Application KPI/QoE Metrics Characterization in SDN
    Software Defined Networking (SDN) presents a unique networking paradigm that facilitates the development of network innovations. This paper aims to improve application awareness by incorporating Machine Learning (ML) techniques within an open source SDN architecture. The paper explores how end-to-end application Key Performance Indicator (KPI) metrics can be designed and utilized for the purpose of application awareness in networks. The main goal of this research is to characterize application KPI metrics using a suitable ML approach based on available network data. Resource allocation and network orchestration tasks can be automated based on the findings. A key facet of this research is introducing a novel feedback interface to the SDN's Northbound Interface that receives realtime performance feedback from applications. This paper aim to show how could we exploit the applications feedback to determine useful characteristics of an application's traffic. A mapping application with a defined KPI is used for experimentation. Linear multiple regression is used to derive a characteristic relationship between the application KPI and the network metrics.
      794Scopus© Citations 22