Quality of experience aware adaptive hypermedia system

The research reported in this thesis proposes, designs and tests a novel Quality of Experience Layer (QoE-layer) for the classic Adaptive Hypermedia Systems (AHS) architecture. Its goal is to improve the end-user perceived Quality of Service in different operational environments suitable for residential users. While the AHS’ main role of delivering personalised content is not altered, its functionality and performance is improved and thus the user satisfaction with the service provided. The QoE Layer takes into account multiple factors that affect Quality of Experience (QoE), such as Web components and network connection. It uses a novel Perceived Performance Model that takes into consideration a variety of performance metrics, in order to learn about the Web user operational environment characteristics, about changes in network connection and the consequences of these changes on the user’s quality of experience. This model also considers the user’s subjective opinion about his/her QoE, increasing its effectiveness and suggests strategies for tailoring Web content in order to improve QoE. The user related information is modelled using a stereotype-based technique that makes use of probability and distribution theory. The QoE-Layer has been assessed through both simulations and qualitative evaluation in the educational area (mainly distance learning), when users interact with the system in a low bit rate operational environment. The simulations have assessed “learning” and “adaptability” behaviour of the proposed layer in different and variable home connections when a learning task is performed. The correctness of Perceived Performance Model (PPM) suggestions, access time of the learning process and quantity of transmitted data were analysed. The results show that the QoE layer significantly improves the performance in terms of the access time of the learning process with a reduction in the quantity of data sent by using image compression and/or elimination. A visual quality assessment confirmed that this image quality reduction does not significantly affect the viewers’ perceived quality that was close to “good” perceptual level. For qualitative evaluation the QoE layer has been deployed on the open-source AHA! system. The goal of this evaluation was to compare the learning outcome, system usability and user satisfaction when AHA! and QoE-ware AHA systems were used. The assessment was performed in terms of learner achievement, learning performance and usability assessment. The results indicate that QoE-aware AHA system did not affect the learning outcome (the students have similar-learning achievements) but the learning performance was improved in terms of study time. Most significantly, QoE-aware AHA provides an important improvement in system usability as indicated by users’ opinion about their satisfaction related to QoE

Thrački konjanik

Today, mobile devices have become an integral part of their possessor’s life. Learning using mobile devices has the advantage of receiving educational content at the moment when it is actually needed, or when the learner feels like s/he is able to study. Moreover, mobile devices used in education can augment the learning experience by delivering further information to the learner, depending on the learner’s context. However, there are still challenges to overcome in order to achieve a widespread adoption of mobile learning. One of these is the high cost of delivering educational content over wireless networks, especially when multimedia content is transmitted. This research proposes a solution that predicts the learner’s economic behaviour and takes it into account when delivering educational multimedia content. A mechanism for reducing the cost of the educational content delivery over wireless networks is also presented

The value of QoE-based adaptation approach in educational hypermedia: Empirical evaluation

Abstract. This paper reports the results of a comparison-based empirical study on the applicability of the end-user Quality of Experience-based content adaptation mechanism in adaptive educational hypermedia. The focus of the paper will be the experiment itself: the initial settings, testing scenarios and the results. We will show that for low bit rate connections the QoE-based adaptation decreases study session time, information processing time per page and the number of re-visits to a page, it maintains similar learning outcomes while also improving the user quality of experience and satisfaction with the system. Finally we will comment on the results and interpret them

Assessing Learning Achievements when Reducing Mobile Video Quality

When using mobile phones for learning purpose, video content is considered to be the preferred type of multimedia content. However, the video file has a big size in comparison to text or audio and might lead to a high delivery cost when transmitted over a mobile network, a cost that not all users are willing to pay. Concerns regarding the monetary cost for accessing data content through mobile networks have been raised by various researchers. A solution that considers the user preference for trading off between video quality and price in order to reduce the content delivery cost is presented. This paper also evaluates the proposed solution and presents the results of an experimental study that assesses the video content adaptation impact on information assimilation. The results show that although the video quality is reduced information assimilation is not negatively affected by the adaptation. This holds true regardless of the mobile device used in the study

What can people risk attitude tell us about people preference for multimedia quality?

Purpose – Multimedia content that is accessible through mobile devices has a larger size than other types of content (e.g. text, images). This may lead to higher prices for accessing the content via mobile devices, as mobile operators are capping mobile data billing plans in an effort to increase their revenues and prevent congestion. This poses problems for the users that are not willing/do not afford to pay the required price but still want to use multimedia content through the mobile networks. A price reduction for the user, as well as minimising bandwidth consumption can be obtained as a trade-off in multimedia quality. However, as previous research shows, not all people are willing to trade-off quality for a lower price; therefore, there is no straightforward approach to this problem. In this context, the purpose of this paper is to present a model of user willingness to pay for multimedia content quality as a function of the user risk attitude with the aim to provide personalised content depending on the user willingness to trade-off price for multimedia content quality. Design/methodology/approach – A user model was proposed based on a literature review and an existing data set. A stereotypical approach was used where users are divided in two groups: risk averse and risk seekers. An experimental study involving six scenarios was used to validate the findings. Findings – The results of the evaluation show that for the proposed user risk model, risk seekers preferred to pay for multimedia quality, whereas risk adverse users preferred to switch to a lower multimedia quality when monetary cost is involved. However, when the mobile data billing plan had the bandwidth limited, rather than a higher price to be paid when the bundle quantity was exceeded, the risk averse people’s preference for a lower quality still holds, but it does not show that most of the risk seekers prefer to pay for the multimedia quality. Research limitations/implications – This paper adds to the state of the art by providing a novel way to model the user preferences for multimedia quality based on their attitude towards risk, age, and gender. Practical implications – Mobile data users, content providers (application service providers, over-the-top providers), mobile network operators (MNOs) and internet service providers (ISPs) could benefit from the results of this research. For mobile data users, the outcome of this research could be beneficial, as they can obtain personalised content based on their needs. From the content providers’ point of view, providing personalised content can lead to more satisfied users. It could also reduce the bandwidth consumption and the traffic to the server and/or proxy. Reducing the bandwidth consumption could lead to the possibility to acquire more customers and hence increase the revenues. Originality/value – This is among the first studies to assess how the user preference towards multimedia quality if affected by the user attitude towards risk

Organizaciones matemáticas y didácticas en torno al objeto de "límite de función" : una propuesta metodológica para el análisis

Our research falls within the general field of the analysis of the teacher's activity and focuses on the specific case of teaching the concept of "limit to the function" in the Spanish secondary school system. Using the anthropological focus of didactics (Chevallard, 1998) as a general theoretical frame, we propose an investigative methodology for the analysis of mathematical organizations recreated by the teacher in the classroom in collaboration with his/her pupils and the respective didactic organizations that allow their reconstruction

Personalisation of the multimedia content delivered to mobile device users

People using mobile devices for studying multimedia based educational content are often on the move and thus rely solely on their device battery power supply. When battery power runs low, they have to stop their activities, significantly reducing their learning outcomes and their satisfaction. This paper proposes a solution to perform the personalisation of the multimedia educational content, based both on the learner profile and on the available power resources on the device used. The solution aims to increase the battery life without affecting learner's quality of experience. Experimental results show that the battery life can be increased by changing streaming related parameters while preliminary subjective tests have assessed their impact on end user perceived quality of the multimedia clip

A Tutoring Framework to Support Computer Science Programmes in Higher Education

Computing Support is the provision of academic supports such as individual tutoring and support classes to students studying computing at third level. Students can struggle with computing as it requires practice involving trial and error. This work proposes a research informed tutoring framework to support computer science students at third level. The tutoring framework combines three pillars; staff and training, pedagogies and activities. Support is put in place to help students develop technical and programming skills. Essential tutoring is provided for those who might otherwise drop out of college. The framework was applied to first and second-year undergraduate programmes and to the first semester in Higher Diploma conversion programmes. Results demonstrate that students\u27 attendance has increased by 14%. In addition, student feedback shows that the framework supports students in computer science. This framework is a useful resource for academic managers that wish to implement computing support at third level

MediaMTool: Multimedia content management tool

With the proliferation of mobile devices, multimedia streaming over wireless networks has increased in popularity. To overcome a number of challenges as well as to enhance mobile users' experience, much research effort has been placed into multimedia content adaptation and personalisation. Supporting adaptive multimedia can pose itself a number of challenges, especially when considering the fast growing rate at which multimedia content is being produced. This paper explores the idea of automatic multimedia content management and authoring to support adaptive multimedia delivery to mobile devices. A multimedia content management tool (MediaMTool) is presented which automatically creates multiple versions of the multimedia clips based on a set of specified multimedia clip features. For testing purposes, MediaMTool was used in conjunction with EcoLearn, a m-learning system that adapts the quality of the educational multimedia clips in order to save battery power on the learner mobile device