Gheorghita Ghinea

Defining user perception of distributed multimedia quality

This article presents the results of a study that explored the human side of the multimedia experience. We propose a model that assesses quality variation from three distinct levels: the network, the media and the content levels; and from two views: the technical and the user perspective. By facilitating parameter variation at each of the quality levels and from each of the perspectives, we were able to examine their impact on user quality perception. Results show that a significant reduction in frame rate does not proportionally reduce the users understanding of the presentation independent of technical parameters, that multimedia content type significantly impacts user information assimilation, user level of enjoyment, and user perception of quality, and that the device display type impacts user information assimilation and user perception of quality. Finally, to ensure the transfer of information, low-level abstraction (network-level) parameters, such as delay and jitter, should be adapted; to maintain the users level of enjoyment, high-level abstraction quality parameters (content-level), such as the appropriate use of display screens, should be adapted.

Software development methods and usability: Perspectives from a survey in the software industry in Norway

This paper investigates the relationship between software development methodologies and usability. The point of departure is the assumption that two important disciplines in software development, one of software development methods (SDMs) and one of usability work, are not integrated in industrial software projects. Building on previous research we investigate two questions; (1) Will software companies generally acknowledge the importance of usability, but not prioritise it in industrial projects? and (2) To what degree are software development methods and usability perceived by practitioners as being integrated? To this end a survey in the Norwegian IT industry was conducted. From a sample of 259 companies we received responses from 78 companies. In response to our first research question, our findings show that although there is a positive bias towards usability, the importance of usability testing is perceived to be much less than that of usability requirements. Given the strong time and cost pressures associated with the software industry, we believe that these results highlight that there is a gap between intention and reality. Regarding our second research question our survey revealed that companies perceive usability and software development methods to be integrated. This is in contrast to earlier research, which, somewhat pessimistically, has argued for the existence of two different cultures, one of software development and one of usability. The findings give hope for the future, in particular because the general use of system development methods are pragmatic and adaptable.

The Perceptual and Attentive Impact of Delay and Jitter in Multimedia Delivery

In this paper we present the results of a study that examines the users perception-understood as both information assimilation and subjective satisfaction-of multimedia quality, when impacted by varying network-level parameters (delay and jitter). In addition, we integrate eye-tracking assessment to provide a more complete understanding of user perception of multimedia quality. Results show that delay and jitter significantly affect user satisfaction; variation in video eye path when either no single/obvious point of focus exists or when the point of attention changes dramatically. Lastly, results showed that content variation significantly affected user satisfaction, as well as user information assimilation.

Stars in their eyes: what eye-tracking reveals about multimedia perceptual quality

Perceptual multimedia quality is of paramount importance to the continued take-up and proliferation of multimedia applications; users will not use and pay for applications if they are perceived to be of low quality. While traditionally distributed multimedia quality has been characterized by quality-of-service (QoS) parameters, these neglect the user perspective of the issue of quality. In order to redress this shortcoming, we characterize the user multimedia perspective using the quality-of-perception (QoP) metric, which encompasses not only a users satisfaction with the quality of a multimedia presentation, but also his/her ability to analyze, synthesize, and assimilate informational content of multimedia. In recognition of the fact that monitoring eye movements offers insights into visual perception, as well as the associated attention mechanisms and cognitive processes, this paper reports on the results of a study investigating the impact of differing multimedia presentation frame rates on user QoP and eye path data. Our results show that provision of higher frame rates, usually assumed to provide better multimedia presentation quality, do not significantly impact upon the median coordinate value of eye path data. Moreover, higher frame rates do not significantly increase the level of participant information assimilation, although they do significantly improve overall user enjoyment and quality perception of the multimedia content being shown.

Quality of perception: user quality of service in multimedia presentations

We define quality of perception (QoP) as representing the user side of the more technical and traditional quality of service. QoP encompasses not only a users satisfaction with the quality of multimedia presentations, but also his/her ability to analyze, synthesise and assimilate the informational content of multimedia displays. We found that significant reductions in frame rate and color depth does not result in a significant QoP degradation.

Olfaction-enhanced multimedia: perspectives and challenges

Olfaction—or smell—is one of the last challenges which multimedia and multimodal applications have to conquer. Enhancing such applications with olfactory stimuli has the potential to create a more complex—and richer—user multimedia experience, by heightening the sense of reality and diversifying user interaction modalities. Nonetheless, olfaction-enhanced multimedia still remains a challenging research area. More recently, however, there have been initial signs of olfactory-enhanced applications in multimedia, with olfaction being used towards a variety of goals, including notification alerts, enhancing the sense of reality in immersive applications, and branding, to name but a few. However, as the goal of a multimedia application is to inform and/or entertain users, achieving quality olfaction-enhanced multimedia applications from the users’ perspective is vital to the success and continuity of these applications. Accordingly, in this paper we have focused on investigating the user perceived experience of olfaction-enhanced multimedia applications, with the aim of discovering the quality evaluation factors that are important from a user’s perspective of these applications, and consequently ensure the continued advancement and success of olfaction-enhanced multimedia applications.

Mulsemedia: State of the Art, Perspectives, and Challenges

Mulsemedia—multiple sensorial media—captures a wide variety of research efforts and applications. This article presents a historic perspective on mulsemedia work and reviews current developments in the area. These take place across the traditional multimedia spectrum—from virtual reality applications to computer games—as well as efforts in the arts, gastronomy, and therapy, to mention a few. We also describe standardization efforts, via the MPEG-V standard, and identify future developments and exciting challenges the community needs to overcome.

Subjective Assessment of Region of Interest-Aware Adaptive Multimedia Streaming Quality

Adaptive multimedia streaming relies on adjusting the video contents bit-rate meet network conditions in the quest to reduce packet loss and resulting video quality degradations. Current multimedia adaptation schemes uniformly adjust the compression over the entire image area. However, research has shown that user attention is focused mostly on certain image areas, denoted areas of maximum user interest (AMUI), and their interest decreases with the increase in distance to the AMUI. The region of interest-based adaptive multimedia streaming scheme (ROIAS) is introduced to perform bit-rate adaptation to network conditions by adjusting video quality relative to the AMUI location. This paper also extends ROIAS to support multiple areas of maximum user interest within the same video frame. This paper presents the performance analysis of ROIAS in terms of the impact on user perceived video quality measured using subjective video quality assessment techniques based on human subjects. The tests use a wide range of video clips, which differ in terms of spatial and temporal complexity and region of interest location and variation. A comparative evaluation of both subjective and objective video quality test results is performed and demonstrate the benefit of using ROIAS for adaptive video quality delivery.

Region of Interest-Based Adaptive Multimedia Streaming Scheme

Adaptive multimedia streaming aims at adjusting the transmitted content based on the available bandwidth such as losses that often severely affect the end-user perceived quality are minimized and consequently the transmission quality increases. Current solutions affect equally the whole viewing area of the multimedia frames, despite research showing that there are regions on which the viewers are more interested in than on others. This paper presents a novel region of interest-based adaptive scheme (ROIAS) for multimedia streaming that when performing transmission-related quality adjustments, selectively affects the quality of those regions of the image the viewers are the least interested in. As the quality of the regions the viewers are the most interested in will not change (or will involve little change), the proposed scheme provides higher overall end-user perceived quality than any of the existing adaptive solutions.

Android vs Windows Mobile vs Java ME: a comparative study of mobile development environments

In this paper we look at three mobile development environments: Windows Mobile, Java ME and Android. Through platform comparison, the different environments are examined closely and strengths and weaknesses are brought to life. In all three environments example applications are written to compare the environments in action on respective devices. Environment specific deployment files are created to illustrate amount of boilerplate code and overhead during deployment. Different key areas such as implementation aspects, performance aspects and quality assurance are compared to give an in depth overview of the status of the different platforms. Our results show that although the three environments are similar in some aspects they still represent three distinctive fields each with their respective characteristics. Through our code examples and platform comparison we come to the conclusion that the Windows Mobile and Android platform provides a better development environment, whereas Java ME still struggles with poor emulator support and incompatible implementations. The main features they have in common are also seen in trends directly visible in the programming languages such as unit testing, language features and end user distribution strategies. Big differences are highlighted when inspecting community environments, hardware abilities and platform maturity. This will have large influence on the choice of development platform for creating novel assistive environment applications.