Satu Jumisko-Pyykkö

Bio: Satu Jumisko-Pyykkö is an academic researcher from Tampere University of Technology. The author has contributed to research in topics: Quality of experience & Quality (business). The author has an hindex of 17, co-authored 52 publications receiving 1525 citations. Previous affiliations of Satu Jumisko-Pyykkö include Eindhoven University of Technology.

Qualinet White Paper on Definitions of Quality of Experience

Abstract: This White Paper is a contribution of the European Network on Quality of Experience in Multimedia Systems and Services, Qualinet (COST Action IC 1003, see www.qualinet.eu), to the scientific discussion about the term "Quality of Experience" (QoE) and its underlying concepts. It resulted from the need to agree on a working definition for this term which facilitates the communication of ideas within a multidisciplinary group, where a joint interest around multimedia communication systems exists, however approached from different perspectives. Thus, the concepts and ideas cited in this paper mainly refer to the Quality of Experience of multimedia communication systems, but may be helpful also for other areas where QoE is an issue. The Network of Excellence (NoE) Qualinet aims at extending the notion of network-centric Quality of Service (QoS) in multimedia systems, by relying on the concept of Quality of Experience (QoE). The main scientific objective is the development of methodologies for subjective and objective quality metrics taking into account current and new trends in multimedia communication systems as witnessed by the appearance of new types of content and interactions. A substantial scientific impact on fragmented efforts carried out in this field will be achieved by coordinating the research of European experts under the catalytic COST umbrella. The White Paper has been compiled on the basis of a first open call for ideas which was launched for the February 2012 Qualinet Meeting held in Prague, Czech Republic. The ideas were presented as short statements during that meeting, reflecting the ideas of the persons listed under the headline "Contributors" in the previous section. During the Prague meeting, the ideas have been further discussed and consolidated in the form of a general structure of the present document. An open call for authors was issued at that meeting, to which the persons listed as "Authors" in the previous section have announced their willingness to contribute in the preparation of individual sections. For each section, a coordinating author has been assigned which coordinated the writing of that section, and which is underlined in the author list preceding each section. The individual sections were then integrated and aligned by an editing group (listed as "Editors" in the previous section), and the entire document was iterated with the entire group of authors. Furthermore, the draft text was discussed with the participants of the Dagstuhl Seminar 12181 "Quality of Experience: From User Perception to Instrumental Metrics" which was held in Schlos Dagstuhl, Germany, May 1-4 2012, and a number of changes were proposed, resulting in the present document. As a result of the writing process and the large number of contributors, authors and editors, the document will not reflect the opinion of each individual person at all points. Still, we hope that it is found to be useful for everybody working in the field of Quality of Experience of multimedia communication systems, and most probably also beyond that field.

Framing the Context of Use for Mobile HCI

Abstract: The need to better understand the role of context has emerged after the revolution of mobile computing, as such devices are used in heterogeneous circumstances. However, it is difficult to say what context of use in mobile human-computer interaction actually means. This study summarises past research in mobile contexts of use and not only provides a deeper understanding of the characteristics associated with it, but also indicates a path for future research. This article presents an extensive and systematic literature review of more than 100 papers published in five high-quality journals and one main conference in the field of HCI during the years 2000-2007. The authors' results show that context of use is still explored as a relatively static phenomenon in mobile HCI. Its most commonly mentioned characteristics are linked to social, physical, and technical components, while transitions between the contexts were rarely listed. Based on this review, a descriptive model of context of use for mobile HCI CoU-HMCI summarising five components, their subcomponents and descriptive properties is presented. The model can help both practitioners and academics to identify broadly relevant contextual factors when designing, experimenting with, and evaluating, mobile contexts of use.

Does context matter in quality evaluation of mobile television

Abstract: Subjective quality evaluation is used to optimize the produced audiovisual quality from fundamental signal processing algorithms to consumer services. These studies typically follow the basic principles of controlled psychoperceptual experiments. However, when compromising compression and transmission parameters for consumer services, the ecological validity of conventional quality evaluation methods can be questioned. To tackle this, we firstly present a novel user-oriented quality evaluation method for mobile television in its usage contexts. Secondly, we present the results of an experiment conducted with 30 participants comparing acceptability and satisfaction of quality as well as goals of viewing in three mobile contexts and under four different residual transmission error rates, when the participants also performed simultaneous assessment tasks. Finally, we compare the results with a previous laboratory experiment. The studied error rates impacted negatively on all measured tasks with some contextual differences. Moreover, the evaluations were more favorable and less discriminate in the mobile contexts compared to the laboratory.

Evaluation of subjective video quality of mobile devices

Abstract: Subjectively perceived video quality is a critical factor when adopting new mobile video applications. When video is used in mobile networks the most important requirements are related to low bitrates, framerates and the screen size of mobile device. In two tests we investigated the effects of codecs and combinations of audio and video streams with low bitrates and different contents on the perceived video quality of mobile devices. The first test showed that the codec H.264 produced the most satisfying video quality, but the quality was not high enough for the presentation of textual information. In the second test, the audio-video ratio 32/128kbps was found to be the most pleasant, but there were content dependent variations.

Designing for user experience: what to expect from mobile 3d tv and video?

Abstract: A long process has been undertaken to develop the technology of 3D video for consumer products, but studies to determine the needs and expectations of actual users have been disregarded. The object of this study is to examine users' needs, expectations and requirements for mobile 3D television and video. We conducted three user studies applying triangulation methodology of the extensive survey, focus groups and probe studies to identify the requirements. The results are presented in the form of guidelines which highlight the characteristics of users, the system and service required including what content is interesting and the context in which it will be used. Both academia and industry can benefit from knowledge of these requirements when designing the further studies and development work concerning the user experience of 3D television and video.

A Survey on Quality of Experience of HTTP Adaptive Streaming

Abstract: Changing network conditions pose severe problems to video streaming in the Internet. HTTP adaptive streaming (HAS) is a technology employed by numerous video services that relieves these issues by adapting the video to the current network conditions. It enables service providers to improve resource utilization and Quality of Experience (QoE) by incorporating information from different layers in order to deliver and adapt a video in its best possible quality. Thereby, it allows taking into account end user device capabilities, available video quality levels, current network conditions, and current server load. For end users, the major benefits of HAS compared to classical HTTP video streaming are reduced interruptions of the video playback and higher bandwidth utilization, which both generally result in a higher QoE. Adaptation is possible by changing the frame rate, resolution, or quantization of the video, which can be done with various adaptation strategies and related client- and server-side actions. The technical development of HAS, existing open standardized solutions, but also proprietary solutions are reviewed in this paper as fundamental to derive the QoE influence factors that emerge as a result of adaptation. The main contribution is a comprehensive survey of QoE related works from human computer interaction and networking domains, which are structured according to the QoE impact of video adaptation. To be more precise, subjective studies that cover QoE aspects of adaptation dimensions and strategies are revisited. As a result, QoE influence factors of HAS and corresponding QoE models are identified, but also open issues and conflicting results are discussed. Furthermore, technical influence factors, which are often ignored in the context of HAS, affect perceptual QoE influence factors and are consequently analyzed. This survey gives the reader an overview of the current state of the art and recent developments. At the same time, it targets networking researchers who develop new solutions for HTTP video streaming or assess video streaming from a user centric point of view. Therefore, this paper is a major step toward truly improving HAS.

Qualinet White Paper on Definitions of Quality of Experience

Abstract: This White Paper is a contribution of the European Network on Quality of Experience in Multimedia Systems and Services, Qualinet (COST Action IC 1003, see www.qualinet.eu), to the scientific discussion about the term "Quality of Experience" (QoE) and its underlying concepts. It resulted from the need to agree on a working definition for this term which facilitates the communication of ideas within a multidisciplinary group, where a joint interest around multimedia communication systems exists, however approached from different perspectives. Thus, the concepts and ideas cited in this paper mainly refer to the Quality of Experience of multimedia communication systems, but may be helpful also for other areas where QoE is an issue. The Network of Excellence (NoE) Qualinet aims at extending the notion of network-centric Quality of Service (QoS) in multimedia systems, by relying on the concept of Quality of Experience (QoE). The main scientific objective is the development of methodologies for subjective and objective quality metrics taking into account current and new trends in multimedia communication systems as witnessed by the appearance of new types of content and interactions. A substantial scientific impact on fragmented efforts carried out in this field will be achieved by coordinating the research of European experts under the catalytic COST umbrella. The White Paper has been compiled on the basis of a first open call for ideas which was launched for the February 2012 Qualinet Meeting held in Prague, Czech Republic. The ideas were presented as short statements during that meeting, reflecting the ideas of the persons listed under the headline "Contributors" in the previous section. During the Prague meeting, the ideas have been further discussed and consolidated in the form of a general structure of the present document. An open call for authors was issued at that meeting, to which the persons listed as "Authors" in the previous section have announced their willingness to contribute in the preparation of individual sections. For each section, a coordinating author has been assigned which coordinated the writing of that section, and which is underlined in the author list preceding each section. The individual sections were then integrated and aligned by an editing group (listed as "Editors" in the previous section), and the entire document was iterated with the entire group of authors. Furthermore, the draft text was discussed with the participants of the Dagstuhl Seminar 12181 "Quality of Experience: From User Perception to Instrumental Metrics" which was held in Schlos Dagstuhl, Germany, May 1-4 2012, and a number of changes were proposed, resulting in the present document. As a result of the writing process and the large number of contributors, authors and editors, the document will not reflect the opinion of each individual person at all points. Still, we hope that it is found to be useful for everybody working in the field of Quality of Experience of multimedia communication systems, and most probably also beyond that field.

The Evolution of Video Quality Measurement: From PSNR to Hybrid Metrics

Abstract: This paper reviews the evolution of video quality measurement techniques and their current state of the art. We start with subjective experiments and then discuss the various types of objective metrics and their uses. We also introduce V-Factor, a "hybrid" metric using both transport- and bitstream information. Finally, we summarize the main standardization activities, such as the work of the video quality experts group (VQEG), and we take a look at emerging trends in quality measurement, including image preference, visual attention, and audiovisual quality.