Evaluation Factors for Multi-Stakeholder Broadband Visual Communication Projects

This paper presents a summary of multifaceted evaluation factors that we have identified through our research with Broadband Visual Communication (BVC) projects involving multiple stakeholders. The main benefit of these evaluation factors is that they provide a general evaluation framework for multiple stakeholder projects. The factors are social infrastructure, technical infrastructure, physical space, interaction style and content

Assessing the quality of audio and video components in desktop multimedia conferencing

This thesis seeks to address the HCI (Human-Computer Interaction) research problem of how to establish the level of audio and video quality that end users require to successfully perform tasks via networked desktop videoconferencing. There are currently no established HCI methods of assessing the perceived quality of audio and video delivered in desktop videoconferencing. The transport of real-time speech and video information across new digital networks causes novel and different degradations, problems and issues to those common in the traditional telecommunications areas (telephone and television). Traditional assessment methods involve the use of very short test samples, are traditionally conducted outside a task-based environment, and focus on whether a degradation is noticed or not. But these methods cannot help establish what audio-visual quality is required by users to perform tasks successfully with the minimum of user cost, in interactive conferencing environments. This thesis addresses this research gap by investigating and developing a battery of assessment methods for networked videoconferencing, suitable for use in both field trials and laboratory-based studies. The development and use of these new methods helps identify the most critical variables (and levels of these variables) that affect perceived quality, and means by which network designers and HCI practitioners can address these problems are suggested. The output of the thesis therefore contributes both methodological (i.e. new rating scales and data-gathering methods) and substantive (i.e. explicit knowledge about quality requirements for certain tasks) knowledge to the HCI and networking research communities on the subjective quality requirements of real-time interaction in networked videoconferencing environments. Exploratory research is carried out through an interleaved series of field trials and controlled studies, advancing substantive and methodological knowledge in an incremental fashion. Initial studies use the ITU-recommended assessment methods, but these are found to be unsuitable for assessing networked speech and video quality for a number of reasons. Therefore later studies investigate and establish a novel polar rating scale, which can be used both as a static rating scale and as a dynamic continuous slider. These and further developments of the methods in future lab- based and real conferencing environments will enable subjective quality requirements and guidelines for different videoconferencing tasks to be established

The Effects of Computer Mediated Communication on the Processes of Communication and Collaboration

This thesis investigates the effects of computer-mediated communication upon collaborative problem solving. The results of three studies are presented, which explore the range of channels of communication afforded by two dissimilar forms of computer-mediated communication. The first study explores the effects of an interactive text-based form of computer-mediated communication, which provides users with a very restricted range of channels. Studies two and three examine the effects of collaborating in a video-mediated context, a technologically sophisticated communication system that affords an array of channels of communication more similar to face-to-face interactions. The effects of these communicative contexts are assessed using a multi-faceted approach. This method of evaluation is based upon analysis of task performance, the structure of the interactions, and measures of the process and content of communication. The findings show that the novice users of these computer-mediated contexts can achieve effective communication and collaboration, but the ease and pace with which this is accomplished varies with communicative context. Users of the highly constrained text-based system initially performed less well on the collaborative tasks, but with experience adapted to the context in appropriate ways. Participants in the video-mediated conditions appeared to adjust quickly to this context. Subtle differences in the structure, process and content of their interactions show that they also had to make allowances for the restraints imposed by the technologically mediated context. These results are discussed within the frame-work of a collaborative model of communication

Understanding interactive behaviour : a quantitative approach.

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