1,288 research outputs found

    Improved online services by personalized recommendations and optimal quality of experience parameters

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    Design, deployment and assessment of a movie archive system in a film studies context

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    This thesis describe our work in developing a movie archive system for students of Film Studies in Dublin City University. In particular, our system uses several recent multimedia technologies to automatically process digital video content but at the same time we use the usability engineering process to relate to the real tasks of real users in their real environments. We investigate how real users take advantage of technologies in a movie browsing system. By designing, building, deploying and assessing the usage of a technology in a user-focused way, the overall impact of a movie browsing system can be determined holistically. The application domain we work in is film studies where students need to study movie contents and analyse movie sequences. Our work began by identification of user needs through observations, focus groups and usability testing, followed by sketching and prototyping a web-based system. We then deployed the system to film study classes over a semester, monitored usage and gathered quantitative as well as qualitative data. Focused experiments were carried out to assess students’ performance and satisfaction levels. Our findings show expected patterns of usage of a real-user setting outside the lab, but at the same time highlighted issues that need to be further investigated. In general, students found most of the provided features were beneficial for their studies. Findings from the experiment shows better performance in the essay assessments and higher satisfaction levels. An interesting finding shows students are more engaged with the newly-introduced software application and take longer time to complete the same task than without the advanced features of the application. This phenomenon was rationalized from established learning theory from the psychology domain. In a technologically-oriented multimedia field today, we attempted to bring in a user-centred approach of end-user interactions throughout a 3-year development process, and we identified benefits and challenges in trying to align the technical perspectives of novel multimedia features to real-world setting

    Semi-synchronous video for deaf telephony with an adapted synchronous codec

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    Magister Scientiae - MScCommunication tools such as text-based instant messaging, voice and video relay services, real-time video chat and mobile SMS and MMS have successfully been used among Deaf people. Several years of field research with a local Deaf community revealed that disadvantaged South African Deaf people preferred to communicate with both Deaf and hearing peers in South African Sign Language as opposed to text. Synchronous video chat and video relay services provided such opportunities. Both types of services are commonly available in developed regions, but not in developing countries like South Africa. This thesis reports on a workaround approach to design and develop an asynchronous video communication tool that adapted synchronous video codecs to store-and-forward video delivery. This novel asynchronous video tool provided high quality South African Sign Language video chat at the expense of some additional latency. Synchronous video codec adaptation consisted of comparing codecs, and choosing one to optimise in order to minimise latency and preserve video quality. Traditional quality of service metrics only addressed real-time video quality and related services. There was no such standard for asynchronous video communication. Therefore, we also enhanced traditional objective video quality metrics with subjective assessment metrics conducted with the local Deaf community.South Afric

    Analyse intelligente de la qualité d'expérience (QoE) dans les réseaux de diffusion de contenu web et mutimédia

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    Today user experience is becoming a reliable indicator for service providers and telecommunication operators to convey overall end to end system functioning. Moreover, to compete for a prominent market share, different network operators and service providers should retain and increase the customers’ subscription. To fulfil these requirements they require an efficient Quality of Experience (QoE) monitoring and estimation. However, QoE is a subjective metric and its evaluation is expensive and time consuming since it requires human participation. Therefore, there is a need for an objective tool that can measure the QoE objectively with reasonable accuracy in real-Time. As a first contribution, we analyzed the impact of network conditions on Video on Demand (VoD) services. We also proposed an objective QoE estimation tool that uses fuzzy expert system to estimate QoE from network layer QoS parameters. As a second contribution, we analyzed the impact of MAC layer QoS parameters on VoD services over IEEE 802.11n wireless networks. We also proposed an objective QoE estimation tool that uses random neural network to estimate QoE from the MAC layer perspective. As our third contribution, we analyzed the effect of different adaption scenarios on QoE of adaptive bit rate streaming. We also developed a web based subjective test platform that can be easily integrated in a crowdsourcing platform for performing subjective tests. As our fourth contribution, we analyzed the impact of different web QoS parameters on web service QoE. We also proposed a novel machine learning algorithm i.e. fuzzy rough hybrid expert system for estimating web service QoE objectivelyDe nos jours, l’expĂ©rience de l'utilisateur appelĂ© en anglais « User Experience » est devenue l’un des indicateurs les plus pertinents pour les fournisseurs de services ainsi que pour les opĂ©rateurs de tĂ©lĂ©communication pour analyser le fonctionnement de bout en bout de leurs systĂšmes (du terminal client, en passant par le rĂ©seaux jusqu’à l’infrastructure des services etc.). De plus, afin d’entretenir leur part de marchĂ© et rester compĂ©titif, les diffĂ©rents opĂ©rateurs de tĂ©lĂ©communication et les fournisseurs de services doivent constamment conserver et accroĂźtre le nombre de souscription des clients. Pour rĂ©pondre Ă  ces exigences, ils doivent disposer de solutions efficaces de monitoring et d’estimation de la qualitĂ© d'expĂ©rience (QoE) afin d’évaluer la satisfaction de leur clients. Cependant, la QoE est une mesure qui reste subjective et son Ă©valuation est coĂ»teuse et fastidieuse car elle nĂ©cessite une forte participation humaine (appelĂ© panel de d’évaluation). Par consĂ©quent, la conception d’un outil qui peut mesurer objectivement cette qualitĂ© d'expĂ©rience avec une prĂ©cision raisonnable et en temps rĂ©el est devenue un besoin primordial qui constitue un challenge intĂ©ressant Ă  rĂ©soudre. Comme une premiĂšre contribution, nous avons analysĂ© l'impact du comportement d’un rĂ©seau sur la qualitĂ© des services de vidĂ©o Ă  la demande (VOD). Nous avons Ă©galement proposĂ© un outil d'estimation objective de la QoE qui utilise le systĂšme expert basĂ© sur la logique floue pour Ă©valuer la QoE Ă  partir des paramĂštres de qualitĂ© de service de la couche rĂ©seau. Dans une deuxiĂšme contribution, nous avons analysĂ© l'impact des paramĂštres QoS de couche MAC sur les services de VoD dans le cadre des rĂ©seaux sans fil IEEE 802.11n. Nous avons Ă©galement proposĂ© un outil d'estimation objective de la QoE qui utilise le rĂ©seau alĂ©atoire de neurones pour estimer la QoE dans la perspective de la couche MAC. Pour notre troisiĂšme contribution, nous avons analysĂ© l'effet de diffĂ©rents scĂ©narios d'adaptation sur la QoE dans le cadre du streaming adaptatif au dĂ©bit. Nous avons Ă©galement dĂ©veloppĂ© une plate-Forme Web de test subjectif qui peut ĂȘtre facilement intĂ©grĂ© dans une plate-Forme de crowd-Sourcing pour effectuer des tests subjectifs. Finalement, pour notre quatriĂšme contribution, nous avons analysĂ© l'impact des diffĂ©rents paramĂštres de qualitĂ© de service Web sur leur QoE. Nous avons Ă©galement proposĂ© un algorithme d'apprentissage automatique i.e. un systĂšme expert hybride rugueux basĂ© sur la logique floue pour estimer objectivement la QoE des Web service

    Taking real steps in virtual nature: a randomized blinded trial

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    Studies show that green exercise (i.e., physical activity in the presence of nature) can provide the synergistic psychophysiological benefits of both physical exercise and nature exposure. The present study aimed to investigate the extent to which virtual green exercise may extend these benefits to people that are unable to engage in active visits to natural environments, as well as to promote enhanced exercise behavior. After watching a video validated to elicit sadness, participants either performed a treadmill walk while exposed to one of two virtual conditions, which were created using different techniques (360° video or 3D model), or walked on a treadmill while facing a blank wall (control). Quantitative and qualitative data were collected in relation to three overarching themes: “Experience,” “Physical engagement” and “Psychophysiological recovery.” Compared to control, greater enjoyment was found in the 3D model, while lower walking speed was found in the 360° video. No significant differences among conditions were found with respect to heart rate, perceived exertion, or changes in blood pressure and affect. The analysis of qualitative data provided further understanding on the participants’ perceptions and experiences. These findings indicate that 3D model-based virtual green exercise can provide some additional benefits compared to indoor exercise, while 360° video-based virtual green exercise may result in lower physical engagement.publishedVersio

    Personal long-term memory aids

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, February 2005.MIT Institute Archives Copy: p. 101-132 bound in reverse order.Includes bibliographical references (p. 126-132).The prevalence and affordability of personal and environmental recording apparatuses are leading to increased documentation of our daily lives. This trend is bound to continue and it follows that academic, industry, and government groups are showing an increased interest in such endeavors for various purposes. In the present case, I assert that such documentation can be used to help remedy common memory problems. Assuming a long-term personal archive exists, when confronted with a memory problem, one faces a new challenge, that of finding relevant memory triggers. This dissertation examines the use of information-retrieval technologies on long-term archives of personal experiences towards remedying certain types of long-term forgetting. The approach focuses on capturing audio for the content. Research on Spoken Document Retrieval examines the pitfalls of information-retrieval techniques on error-prone speech- recognizer-generated transcripts and these challenges carry over to the present task. However, "memory retrieval" can benefit from the person's familiarity of the recorded data and the context in which it was recorded to help guide their effort. To study this, I constructed memory-retrieval tools designed to leverage a person's familiarity of their past to optimize their search task. To evaluate the utility of these towards solving long-term memory problems, I (1) recorded public events and evaluated witnesses' memory-retrieval approaches using these tools; and (2) conducted a longer- term memory-retrieval study based on recordings of several years of my personal and research-related conversations. Subjects succeeded with memory-retrieval tasks in both studies, typically finding answers within minutes.(cont.) This is far less time than the alternate of re-listening to hours of recordings. Subjects' memories of the past events, in particular their ability to narrow the window of time in which past events occurred, improved their ability to find answers. In addition to results from the memory-retrieval studies, I present a technique called "speed listening." By using a transcript (even one with many errors), it allows people to reduce listening time while maintaining comprehension. Finally, I report on my experiences recording events in my life over 2.5 years.by Sunil Vemuri.Ph.D

    A Virtual University Infrastructure For Orthopaedic Surgical Training With Integrated Simulation

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    This thesis pivots around the fulcrum of surgical, educational and technological factors. Whilst there is no single conclusion drawn, it is a multidisciplinary thesis exploring the juxtaposition of different academic domains that have a significant influence upon each other. The relationship centres on the engineering and computer science factors in learning technologies for surgery. Following a brief introduction to previous efforts developing surgical simulation, this thesis considers education and learning in orthopaedics, the design and building of a simulator for shoulder surgery. The thesis considers the assessment of such tools and embedding into a virtual learning environment. It explains how the performed experiments clarified issues and their actual significance. This leads to discussion of the work and conclusions are drawn regarding the progress of integration of distributed simulation within the healthcare environment, suggesting how future work can proceed

    Estimation of the QoE for video streaming services based on facial expressions and gaze direction

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    As the multimedia technologies evolve, the need to control their quality becomes even more important making the Quality of Experience (QoE) measurements a key priority. Machine Learning (ML) can support this task providing models to analyse the information extracted by the multimedia. It is possible to divide the ML models applications in the following categories: 1) QoE modelling: ML is used to define QoE models which provide an output (e.g., perceived QoE score) for any given input (e.g., QoE influence factor). 2) QoE monitoring in case of encrypted traffic: ML is used to analyze passive traffic monitored data to obtain insight into degradations perceived by end-users. 3) Big data analytics: ML is used for the extraction of meaningful and useful information from the collected data, which can further be converted to actionable knowledge and utilized in managing QoE. The QoE estimation quality task can be carried out by using two approaches: the objective approach and subjective one. As the two names highlight, they are referred to the pieces of information that the model analyses. The objective approach analyses the objective features extracted by the network connection and by the used media. As objective parameters, the state-of-the-art shows different approaches that use also the features extracted by human behaviour. The subjective approach instead, comes as a result of the rating approach, where the participants were asked to rate the perceived quality using different scales. This approach had the problem of being a time-consuming approach and for this reason not all the users agree to compile the questionnaire. Thus the direct evolution of this approach is the ML model adoption. A model can substitute the questionnaire and evaluate the QoE, depending on the data that analyses. By modelling the human response to the perceived quality on multimedia, QoE researchers found that the parameters extracted from the users could be different, like Electroencephalogram (EEG), Electrocardiogram (ECG), waves of the brain. The main problem with these techniques is the hardware. In fact, the user must wear electrodes in case of ECG and EEG, and also if the obtained results from these methods are relevant, their usage in a real context could be not feasible. For this reason, my studies have been focused on the developing of a Machine Learning framework completely unobtrusively based on the Facial reactions

    MediaSync: Handbook on Multimedia Synchronization

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    This book provides an approachable overview of the most recent advances in the fascinating field of media synchronization (mediasync), gathering contributions from the most representative and influential experts. Understanding the challenges of this field in the current multi-sensory, multi-device, and multi-protocol world is not an easy task. The book revisits the foundations of mediasync, including theoretical frameworks and models, highlights ongoing research efforts, like hybrid broadband broadcast (HBB) delivery and users' perception modeling (i.e., Quality of Experience or QoE), and paves the way for the future (e.g., towards the deployment of multi-sensory and ultra-realistic experiences). Although many advances around mediasync have been devised and deployed, this area of research is getting renewed attention to overcome remaining challenges in the next-generation (heterogeneous and ubiquitous) media ecosystem. Given the significant advances in this research area, its current relevance and the multiple disciplines it involves, the availability of a reference book on mediasync becomes necessary. This book fills the gap in this context. In particular, it addresses key aspects and reviews the most relevant contributions within the mediasync research space, from different perspectives. Mediasync: Handbook on Multimedia Synchronization is the perfect companion for scholars and practitioners that want to acquire strong knowledge about this research area, and also approach the challenges behind ensuring the best mediated experiences, by providing the adequate synchronization between the media elements that constitute these experiences
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