Understanding user experience of mobile video: Framework, measurement, and optimization

Since users have become the focus of product/service design in last decade, the term User eXperience (UX) has been frequently used in the field of Human-Computer-Interaction (HCI). Research on UX facilitates a better understanding of the various aspects of the user’s interaction with the product or service. Mobile video, as a new and promising service and research field, has attracted great attention. Due to the significance of UX in the success of mobile video (Jordan, 2002), many researchers have centered on this area, examining users’ expectations, motivations, requirements, and usage context. As a result, many influencing factors have been explored (Buchinger, Kriglstein, Brandt & Hlavacs, 2011; Buchinger, Kriglstein & Hlavacs, 2009). However, a general framework for specific mobile video service is lacking for structuring such a great number of factors. To measure user experience of multimedia services such as mobile video, quality of experience (QoE) has recently become a prominent concept. In contrast to the traditionally used concept quality of service (QoS), QoE not only involves objectively measuring the delivered service but also takes into account user’s needs and desires when using the service, emphasizing the user’s overall acceptability on the service. Many QoE metrics are able to estimate the user perceived quality or acceptability of mobile video, but may be not enough accurate for the overall UX prediction due to the complexity of UX. Only a few frameworks of QoE have addressed more aspects of UX for mobile multimedia applications but need be transformed into practical measures. The challenge of optimizing UX remains adaptations to the resource constrains (e.g., network conditions, mobile device capabilities, and heterogeneous usage contexts) as well as meeting complicated user requirements (e.g., usage purposes and personal preferences). In this chapter, we investigate the existing important UX frameworks, compare their similarities and discuss some important features that fit in the mobile video service. Based on the previous research, we propose a simple UX framework for mobile video application by mapping a variety of influencing factors of UX upon a typical mobile video delivery system. Each component and its factors are explored with comprehensive literature reviews. The proposed framework may benefit in user-centred design of mobile video through taking a complete consideration of UX influences and in improvement of mobile videoservice quality by adjusting the values of certain factors to produce a positive user experience. It may also facilitate relative research in the way of locating important issues to study, clarifying research scopes, and setting up proper study procedures. We then review a great deal of research on UX measurement, including QoE metrics and QoE frameworks of mobile multimedia. Finally, we discuss how to achieve an optimal quality of user experience by focusing on the issues of various aspects of UX of mobile video. In the conclusion, we suggest some open issues for future study

Packet loss visibility across SD, HD, 3D, and UHD video streams

The trend towards video streaming with increased spatial resolutions and dimensions, SD, HD, 3D, and 4kUHD, even for portable devices has important implications for displayed video quality. There is an interplay between packetization, packet loss visibility, choice of codec, and viewing conditions, which implies that prior studies at lower resolutions may not be as relevant. This paper presents two sets of experiments, the one at a Variable BitRate (VBR) and the other at a Constant BitRate (CBR), which highlight different aspects of the interpretation. The latter experiments also compare and contrast encoding with either an H.264 or an High Efficiency Video Coding (HEVC) codec, with all results recorded as objective Mean Opinion Score (MOS). The video quality assessments will be of interest to those considering: the bitrates and expected quality in error-prone environments; or, in fact, whether to use a reliable transport protocol to prevent all errors, at a cost in jitter and latency, rather than tolerate low levels of packet errors

Bridging the Gap Between Imaging Performance and Image Quality Measures

Imaging system performance measures and Image Quality Metrics (IQM) are reviewed from a systems engineering perspective, focusing on spatial quality of still image capture systems. We classify IQMs broadly as: Computational IQMs (CPIQM), Multivariate Formalism IQMs (MF-IQM), Image Fidelity Metrics (IF-IQM), and Signal Transfer Visual IQMs (STV-IQM). Comparison of each genre finds STV-IQMs well suited for capture system quality evaluation: they incorporate performance measures relevant to optical systems design, such as Modulation Transfer Function (MTF) and Noise-Power Spectrum (NPS); their bottom, modular approach enables system components to be optimised separately. We suggest that correlation between STV IQMs and observer quality scores is limited by three factors: current MTF and NPS measures do not characterize scene-dependent performance introduced by imaging system non-linearities; contrast sensitivity models employed do not account for contextual masking effects; cognitive factors are not considered. We hypothesise that implementation of scene and process-dependent MTF (SPD-MTF) and NPS (SPD-NPS) measures should mitigate errors originating from scene dependent system performance. Further, we propose implementation of contextual contrast detection and discrimination models to better represent low-level visual performance in image quality analysis. Finally, we discuss image quality optimization functions that may potentially close the gap between contrast detection/discrimination and quality

El parámetro estilo en los estudios de calidad y de expectativas de la Interpretación Simultánea

This study focuses on the analysis of the style parameter, which is one of the nine parameters established by Bühler (1986) to evaluate the quality of an interpretation, and its impact on conference interpretations. Three studies have been designed to analyze the replies of a group of specialized users, and how the subjects understand the concept of ‘style’. These studies also show the effect of a manipulation to create an excessively complex style on the recipients of the interpretation, users’ expectations, and the interaction of this parameter with others, both verbal and non-verbal. Although the study indicates the lack of consensus when it comes to a definition of the concept of style, it also shows that its significance may be greater than that which has been attributed to it so far in the field of interpretation.Este estudio se centra en el análisis del parámetro estilo, uno de los nueve parámetros de calidad de la interpretación establecidos por Bühler (1986), y su impacto en la interpretación de conferencias. Mediante tres estudios llevados a cabo, se han analizado las respuestas de un grupo de usuarios especializados. En estos estudios se muestra el grado de conceptualización del parámetro estilo, su influencia en el usuario dependiendo de la metodología aplicada, las expectativas del usuario, la interacción del parámetro con otros parámetros tanto verbales como no verbales y los efectos del empleo de un estilo inapropiado. Si bien el estudio señala la falta de consenso en la definición del concepto estilo, muestra también que su papel puede ser más relevante que el que hasta ahora se le atribuye en la interpretación

When For-Profit Companies Evaluate Potential Nonprofit Partners Focused on Youth Development, what is the Role of Symbolic Brand Association in that Evaluation?

Literature suggests that, “symbolic associations refer to the abstract cognitions that translate the values of the organization, personality traits associated with the brand and even emotions” (Michaelidou, Micevski, & Cadogan, 2015, p. 1658). Here, in order to measure the value of clear and powerful symbolic brand associations for nonprofits as they seek corporate support, commercial managers evaluated the symbolic brand associations of five nonprofit organizations devoted to youth development through sport. This type of commercial-nonprofit linkage warranted analysis due to the association benefits offered by both sport and youth. Professionals in this sector, standard literature from both commercial and nonprofit sectors, and current professional resources give us a background on the intricacies of the partnership marketplace as it exists today, offering potential reasons for each sector to engage in mutual partnership. This research adds to the literature by helping us determine the role that symbolic brand associations have in this intersection and by helping nonprofit managers understand the value of such associations in a process full of brief psychological judgment. Usefulness, efficiency, dynamism, affect, reliability, ethicality, and typicality were the measured associations. Affect (compassionate, favorable, friendly) and reliability (responsible, reputable, sincere) of the nonprofit were the two associations that correlated most strongly with corporate engagement (money, time, resources, partnership, leveraging). This correlation underscores the value of clearly articulated symbolic brand associations. Strategies from literature and examples from successful corporate development teams in the nonprofit sector begin to help us understand how symbolic associations are used to create relevance for nonprofits that can use these associations to find connections and grow their corporate alliances

Eye quietness and quiet eye in expert and novice golf performance: an electrooculographic analysis

Quiet eye (QE) is the final ocular fixation on the target of an action (e.g., the ball in golf putting). Camerabased eye-tracking studies have consistently found longer QE durations in experts than novices; however, mechanisms underlying QE are not known. To offer a new perspective we examined the feasibility of measuring the QE using electrooculography (EOG) and developed an index to assess ocular activity across time: eye quietness (EQ). Ten expert and ten novice golfers putted 60 balls to a 2.4 m distant hole. Horizontal EOG (2ms resolution) was recorded from two electrodes placed on the outer sides of the eyes. QE duration was measured using a EOG voltage threshold and comprised the sum of the pre-movement and post-movement initiation components. EQ was computed as the standard deviation of the EOG in 0.5 s bins from –4 to +2 s, relative to backswing initiation: lower values indicate less movement of the eyes, hence greater quietness. Finally, we measured club-ball address and swing durations. T-tests showed that total QE did not differ between groups (p = .31); however, experts had marginally shorter pre-movement QE (p = .08) and longer post-movement QE (p < .001) than novices. A group × time ANOVA revealed that experts had less EQ before backswing initiation and greater EQ after backswing initiation (p = .002). QE durations were inversely correlated with EQ from –1.5 to 1 s (rs = –.48 - –.90, ps = .03 - .001). Experts had longer swing durations than novices (p = .01) and, importantly, swing durations correlated positively with post-movement QE (r = .52, p = .02) and negatively with EQ from 0.5 to 1s (r = –.63, p = .003). This study demonstrates the feasibility of measuring ocular activity using EOG and validates EQ as an index of ocular activity. Its findings challenge the dominant perspective on QE and provide new evidence that expert-novice differences in ocular activity may reflect differences in the kinematics of how experts and novices execute skills

Journal of Applied Communications vol. 98 (3) Full Issue

Journal of Applied Communications vol. 98 (3) - Full Issu

Adolescence, autism and technology: how technology can impact the social lives and wellbeing of adolescents with an autism diagnosis

Section A Section A is a narrative review of social skills interventions that have been used to enhance the social skills of adolescents with a diagnosis of autism. The review examined the types of interventions used as well as their efficacy, acceptability and generalisability. Exploration of the research revealed some limited evidence supporting the use of technology-delivered social skills interventions. Interventions offered little benefit over in-person interventions and limited generalisability. However, such interventions were positively received by young people which may improve intervention adherence. Clinical and research implications are provided. Section B Section B is a mixed-methods study examining the social media experiences of 222 adolescents with and without autistic traits. Participants’ views on the advantages and disadvantages of using social media and its impact on their social life were collected. A number of hypotheses concerning social media’s impact on social capital and wellbeing were tested, including the moderating role of autistic traits. Results show that social media use can have a positive impact on adolescents’ social lives and improve online social capital. Its impact on wellbeing appeared to vary depending on autistic traits. Findings are discussed in terms of their implications for clinical practice. Limitations are considered and implications for future research are provided