Optimized Adaptive Streaming Representations based on System Dynamics

Adaptive streaming addresses the increasing and heterogenous demand of multimedia content over the Internet by offering several encoded versions for each video sequence. Each version (or representation) has a different resolution and bit rate, aimed at a specific set of users, like TV or mobile phone clients. While most existing works on adaptive streaming deal with effective playout-control strategies at the client side, we take in this paper a providers' perspective and propose solutions to improve user satisfaction by optimizing the encoding rates of the video sequences. We formulate an integer linear program that maximizes users' average satisfaction, taking into account the network dynamics, the video content information, and the user population characteristics. The solution of the optimization is a set of encoding parameters that permit to create different streams to robustly satisfy users' requests over time. We simulate multiple adaptive streaming sessions characterized by realistic network connections models, where the proposed solution outperforms commonly used vendor recommendations, in terms of user satisfaction but also in terms of fairness and outage probability. The simulation results further show that video content information as well as network constraints and users' statistics play a crucial role in selecting proper encoding parameters to provide fairness a mong users and to reduce network resource usage. We finally propose a few practical guidelines that can be used to choose the encoding parameters based on the user base characteristics, the network capacity and the type of video content

Impact of Coronavirus Disease-19 Lockdown on Egyptian Children and Adolescents: Dietary Pattern Changes Health Risk

BACKGROUND: Lockdown and school closure related to the coronavirus disease 2019 (COVID-19) have unfavorable effects on children and adolescents. AIM: This study was conducted to survey the changes in dietary pattern and related health factors in Egyptian children and adolescents during the COVID-19 outbreak closure. MATERIALS AND METHODS: Data were collected through a dietary pattern, eating behavior, and physical activity electronic questionnaire conducted through social media sites, targeting parents of children and adolescents after two whole months of lockdown and school closure in Egypt. RESULTS: This study included 765 participants, 31.8% noted increased appetite, 45.6% reported increased sweets and unhealthy food consumption, and 37.6% showed increased frequent snacking between meals. Alongside 53.1% showed increase in late snacks during night after COVID-19 closure. The majority of our participants 82.0% noted associative change in eating behavior with boring and 94.6% revealed increased usage of electronics and screen time. This study showed significant positive correlation between increased appetite and mobile screen time, laptop screen time, and video gaming. Increased sweets and unhealthy food consumption was positively correlated with TV watching and mobile screen time. A significant positive correlation was revealed between uncaring about eating fruits and vegetables and increase screen time for each of mobile, and laptop and remote learning. Furthermore, there was positive correlation between decreased protein serving intake and each of mobile screen time and remote learning. TV watching and laptop screen times showed positively significantly association with frequent snacking between meals. Mobile screen time, TV screen time, and video gaming were positively significantly correlated with late night snacking. CONCLUSIONS: The present study concluded prolonged lockdown leads to changes in eating patterns, related to contributing factors of physical inactivity and prolonged screen time

"Hyperconnected” adolescents: sedentary screen time according to gender and type of day

The research objective was to know the mean daily usage time of screen-based devices (Television [TV], computer, video games, and mobile phone), as well as compliance with screen time recommendations for these devices. Likewise, the differences in the four electronic devices were examined according to gender and type of day (i.e., weekdays and weekend). A total of 2021 adolescents (M age=14.23; SD=1.58; 51% female) completed a questionnaire on regular screen time usage. The young people reported a mean daily screen usage of 6 hours and 12 minutes, with 4% of them meeting screen time recommendations (<2 hours/day). No differences in total screen time usage were obtained according to gender. However, boys obtained higher values in the use of video games, while girls obtained higher values in the use of mobile phones and computers. Adolescents reported higher screen time values at weekends than on weekdays in terms of all four electronic devices analysed. On the basis of the high daily screen usage time, developing strategies towards the responsible use of video games in boys, and mobile phones and computers in girls, seems necessary, placing emphasis on weekend days. El objetivo del estudio fue conocer el tiempo medio de uso diario de cuatro medios tecnológicos de pantalla (MTP) (TV, ordenador, videojuegos y teléfono móvil), así como el cumplimiento de las recomendaciones de pantalla en dichos dispositivos. Asimismo, se examinaron las diferencias en los cuatro MTP en función del género y el tipo de jornada. Un total de 2021 adolescentes (M edad=14.23; DT=1.58; 51% chicas) cumplimentaron un cuestionario sobre el uso habitual de tiempo de pantalla. Los jóvenes reportaron un uso medio diario de pantalla de 6 horas y 12 minutos, cumpliendo un 4% las recomendaciones de tiempo pantalla (<2 horas/día). No se obtuvieron diferencias en el tiempo de uso total de pantalla en función del género. Sin embargo, los chicos obtuvieron valores superiores en el uso de videojuegos, mientras que las chicas obtuvieron valores superiores en la utilización del teléfono móvil y el ordenador. Durante el fin de semana, los adolescentes reportaron valores superiores de tiempo pantalla, en los cuatro MTP analizados, que entre semana. En base al elevado tiempo de uso diario de pantalla, parece necesario el desarrollo de estrategias en el uso responsable de videojuegos en los chicos y en el teléfono móvil y el ordenador en las chicas, haciendo énfasis en los fines de semana

Self-reported dependence on mobile phones in young adults: a European cross-cultural empirical survey

Background and aims: Despite many positive benefits, mobile phone use can be associated with harmful and detrimental behaviors. The aim of this study was twofold: to examine (a) cross-cultural patterns of perceived dependence on mobile phones in ten European countries, first, grouped in four different regions (North: Finland and UK; South: Spain and Italy; East: Hungary and Poland; West: France, Belgium, Germany, and Switzerland), and second by country, and (b) how socio-demographics, geographic differences, mobile phone usage patterns, and associated activities predicted this perceived dependence. Methods: A sample of 2,775 young adults (aged 18–29 years) were recruited in different European Universities who participated in an online survey. Measures included socio-demographic variables, patterns of mobile phone use, and the dependence subscale of a short version of the Problematic Mobile Phone Use Questionnaire (PMPUQ; Billieux, Van der Linden, & Rochat, 2008). Results: The young adults from the Northern and Southern regions reported the heaviest use of mobile phones, whereas perceived dependence was less prevalent in the Eastern region. However, the proportion of highly dependent mobile phone users was more elevated in Belgium, UK, and France. Regression analysis identified several risk factors for increased scores on the PMPUQ dependence subscale, namely using mobile phones daily, being female, engaging in social networking, playing video games, shopping and viewing TV shows through the Internet, chatting and messaging, and using mobile phones for downloading-related activities. Discussion and conclusions: Self-reported dependence on mobile phone use is influenced by frequency and specific application usage

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 &amp; Hlavacs, 2011; Buchinger, Kriglstein &amp; 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

Will mobile video become the killer application for 3G? - an empirical model for media convergence

Mobile carriers have continually rolled out 3G mobile video applications to increase their revenue and profits. The presumption is that video is superior to the already successful SMS, ringtones, and pictures, and can create greater value to users. However, recent market surveys revealed contradicting results. Motivated by this discrepancy, we propose in this paper a parsimonious model for user acceptance of mobile entertainment as digital convergence. Integrating research on Information Systems, Flow, and Media Psychology, we take a unique approach to user acceptance of digital convergence - platform migration. Our key proposition is that the interaction between media types and the platform-specific constraints is the key determinant of user evaluation. Particularly, users' involvement in the media is determined by both the entertaining time span on the original platform and the attentional constraint of the new platform. The mismatch between the two spans can result in lower level involvement, which in turn cause no or even negative user emotional responses. The model was tested with empirical data. We discuss the theoretical contributions, strategic and design implications, and future research directions derived from this theoretical framewor

Subjective evaluation of the video transmission quality over a commercial mobile network

V pričujočem diplomskem delu je predstavljeno subjektivno ocenjevanje kakovosti video posnetkov, procesiranih preko naprave Ikusnet, ki omogoča prenos podatkov preko komercialnega mobilnega podatkovnega omrežja LTE, za potrebe televizijske produkcije. Glavni cilj dela je ugotoviti, ali naprava Ikusnet ustreza kriterijem kakovosti video posnetkov televizijske produkcije RTV Slovenija. Uvodoma opišemo napravo Ikusnet, njene lastnosti, načine delovanja in področja uporabe, kot tudi namen uporabe na RTV Slovenija. Sledi predstavitev metod subjektivnega ocenjevanja kakovosti video posnetkov in njihovih prednosti. Nato predstavimo izvedbo testiranja, ki je zajemalo prenos video posnetkov z napravo Ikusnet preko komercialnega mobilnega podatkovnega omrežja LTE ter izvedbo subjektivnega ocenjevanja kakovosti prenesenih posnetkov. Rezultati ocenjevanja kažejo, da naprava Ikusnet ne zagotavlja primerne kakovosti prenosa video posnetkov za distribucijo daljših TV signalov, ustreza pa kriterijem RTV Slovenija za načrtovana in naključna javljanja v oddaje. V zaključku sledi krajša razprava o možnostih uporabe naprav za prenos TV signalov preko komercialnega mobilnega podatkovnega omrežja LTE.This thesis presents a subjective quality assessment of video processed through the device Ikusnet, which enables data transmission via a commercial LTE mobile data network for the needs of TV broadcasting. The main objective of the thesis is to determine whether Ikusnet meets the video quality criteria for RTV Slovenia\u27s TV production. The description, features, modes of operation and applications of the device Ikusnet by Prodys are given in the initial chapter, as well as the purpose of the device\u27s use at RTV Slovenia. Next, we present different methods of subjective video quality assessment and their advantages. This is followed by a description of the implementation of the video quality assessment, which entailed video transmission via a commercial LTE mobile data network and subsequent subjective quality assessment of the transmitted footage. Results indicate that Ikusnet does not provide adequate video quality for longer TV broadcasting signals. On the other hand, it satifies the criteria of RTV Slovenia for planned and ad-hoc news broadcasts of shorther length. We conclude with a discussion of the possibilities of the device\u27s usage that allow for the transfer of broadcasting TV signals via a commercial LTE mobile data network

Spectrum trading with interference rights

Spectrum, which supports the transmission of sound, data, and video, is critical to the implementation of mobile connected society. Federal Communications Commission (FCC) has been seeking policies that offer more spectrum access opportunities, such as secondary spectrum market and TV white space. In this paper, we develop the idea of trading spectrum in Interference Right. It means to alleviate the spectrum scarcity by cooperative spectrum usage and making the spectrum market as liquid as possible. We use some plausible case studies to illustrate the characteristics and features. The paper therefore includes a detailed description of trading procedures along with some first order quantitative modeling of the cases coupled with qualitative analysis. © 2012 ICST

Quality delivery of mobile video: In-depth understanding of user requirements

The increase of powerful mobile devices has accelerated the demand for mobile videos. Previous studies in mobile video have focused on understanding of mobile video usage, improvement of video quality, and user interface design in video browsing. However, research focusing on a deep understanding of users’ needs for a pleasing quality delivery of mobile video is lacking. In particular, what quality-delivery mode users prefer and what information relevant to video quality they need requires attention. This paper presents a qualitative interview study with 38 participants to gain an insight into three aspects: influencing factors of user-desired video quality, user-preferred quality-delivery modes, and user-required interaction information of mobile video. The results show that user requirements for video quality are related to personal preference, technology background and video viewing experience, and the preferred quality-delivery mode and interactive mode are diverse. These complex user requirements call for flexible and personalised quality delivery and interaction of mobile video