Desktop Videoconferencing System Research Articles

Sequences of normative evaluation in two telecollaboration projects: A comparative study of multimodal feedback through desktop videoconference

Abstract In our study we analyse how the same interactional dynamic is produced in two different pedagogical settings exploiting a desktop videoconference system. We propose to focus our attention on a specific type of conversational side sequence, known in the Francophone literature as sequences of normative evaluation. More particularly, we analyse data from two telecollaborative projects through desktop videoconference: a French-Chinese tandem, and a French-Irish telecollaboration between trainee teachers and learners of French as a foreign language. The comparison of two different pedagogical settings allows us to understand what types of interactional dynamics are co-constructed through the desktop videoconference environment and which characteristics are specific to each pedagogical setting. Within a socio-interactionist perspective, we analysed four hours of interactions, focusing particularly on the transmodal enactment of the sequences under scrutiny and its relation to learners’ uptake. Our results show on the one hand that there are some quantitative differences in the production of sequences of normative evaluation between the two pedagogical settings, and on the other hand that, contrary to our hypothesis, the co-construction of these sequences does not differ in multimodal density across the two contexts. We discuss these results and propose some tentative explanations for them.

The Impact of Collaborative Style on the Perception of 2D and 3D Videoconferencing Interfaces

Video-based collaborative virtual environments (CVE) attempt to emulate face-to-face meetings by immersing remote collaborators in a shared 3D virtual setting. To investigate potential advantages of this novel type of collaborative user interfaces for creating a better sense of social presence and affording a more efficient collaborative process we con- ducted an empirical study in which pairs of users solved a simple task (matching a set of celebrity photos with a set of quotes) using four different media: face-to-face, a standard desktop videoconferencing system (VC), a desktop video- CVE, and a stereo large-screen video-CVE. As expected, results showed that face-to-face provided a significantly stronger sense of social presence than any of the systems, but relatively little differences showed between the systems themselves. However, significant gender effects emerged in an ex-post analysis for the different system types, with females perceiving more social presence when using the standard video conferencing environment and less with the video-CVE conditions, while males showed the opposite effect. Linguistic analysis of audio transcriptions and video analysis further illuminates differences between collaboration styles of males and females across the collaborative conditions. We discuss the implica- tions of our findings for future studies into CVEs and video conferencing systems.

A Multiparty Videoconferencing System Over an Application-Level Multicast Protocol

Increased speeds of PCs and networks have made media communications possible on the Internet. Today, the need for desktop videoconferencing is experiencing robust growth in both business and consumer markets. However, the synchronous delivery of high-volume media content is still a big challenge under a current heterogeneous Internet environment. In this paper, we present a multiparty videoconferencing system based on a peer-to-peer (P2P) solution. The contribution of our paper is twofold. On the one hand, we design an application-level multicast scheme which intends to tolerate the heterogeneity in videoconferencing applications. Design tradeoffs are analyzed and our decisions are made based on extensive experimentation. On the other, we design a five-layer architecture for implementing a multiparty videoconferencing system. This architecture makes a clear-cut distinction between different functional modules and therefore provides rich flexibility in feature adaptation. We believe that our work can be a helpful reference in other efforts on building desktop videoconferencing systems.

A rating scheme for assessing the quality of computer-supported collaboration processes

The analysis of the process of collaboration is a central topic in current CSCL research. However, defining process characteristics relevant for collaboration quality and developing instruments capable of assessing these characteristics are no trivial tasks. In the assessment method presented in this paper, nine qualitatively defined dimensions of collaboration are rated quantitatively: sustaining mutual understanding, dialogue management, information pooling, reaching consensus, task division, time management, technical coordination, reciprocal interaction, and individual task orientation. The data basis for the development of these dimensions was taken from a study in which students of psychology and medicine collaborated on a complex patient case via a desktop-videoconferencing system. A qualitative content analysis was performed on a sample of transcribed collaboration dialogue. The insights from this analysis were then integrated with theoretical considerations about the roles of communication, joint information processing, coordination, interpersonal relationship, and motivation in the collaboration process. The resulting rating scheme was applied to process data from a new sample of 40 collaborating dyads. Based on positive findings on inter-rater reliability, consistency, and validity from this evaluation, we argue that the new method can be recommended for use in different areas of CSCL.

Desktop Videoconferencing: Examples of Applications to Support Teacher Training in Rural Areas

This article presents examples of desktop videoconferencing used as a tool for supporting teacher training, particularly in rural settings. The accessibility of videoconferencing desktop systems makes it possible to directly observe and supervise students in actual teaching situations. Videoconferencing presents unique opportunities for working with students in rural settings, as well as other students with limited access to university programs. The benefits and challenges of using desktop videoconferencing are discussed. The discussion section addresses the need for additional research to determine the appropriate application of desktop videoconferencing systems as the technology becomes more available for school use.

Differences between `talking about' and `admitting' sensitive behaviour in anonymous and non-anonymous web-based interviews

This paper examines the differences between two factors of the tendency to give socially desirable answers in regard to sensitive questions. In contrast to the usual question of how socially desirable a certain behaviour is perceived by the interviewee, a study performed at the University of Bremen divided this question into `talking about' and `admitting' a certain behaviour, where `talking about' meant to mention a certain behaviour in public while `admitting' implied that one has already done it oneself. Additionally, the study compared two different computer mediated interview modes: a web-based questionnaire (ONLINE) and an innovative method called internet assisted personal interview (IAPI), which used a desktop video conference system to facilitate communication between the interviewer and the interviewee. This was done in order to compare the tendency to give socially desirable answers in an anonymous (ONLINE) and non-anonymous (IAPI) interview setting. Results show that there are significant differences between most of the `talking about' and `admitting' items. Nevertheless, the expected differences between the interview modes were not observed.

The impact of videoconference technology, interview structure, and interviewer gender on interviewer evaluations in the employment interview: A field experiment

Despite the growing use of communication technologies, such as videoconferencing, in recruiting and selection, there is little research examining whether these technologies influence interviewers' perceptions of candidates. The present field experiment analysed evaluations of 92 real job applicants who were randomly assigned either to be interviewed face‐to‐face (FTF) (N = 48) or using a desktop videoconference system (N = 44). The results show a bias in favour of the videoconference applicants relative to FTF applicants, F(1,91) = 7.35, p = .01. A significant interaction of interview structure and interviewer gender was also found, F(1,91) = 3.70, p < .05, with female interviewers using an unstructured interview rating applicants significantly higher than males or females using a structured interview. Interview structure did not significantly moderate the influence of interview medium on interviewers' evaluations of applicants. These findings highlight the need to be aware of potential biases resulting from the use of communication technologies in the hiring process.

A study of the application sharing capabilities in telemedicine

The main aim of this study was to find out if the image format (TIFF or JPEG) influenced the time delay for transferring radiological images by the application sharing tool of a desktop videoconferencing system. The second task of the study was to define a procedure that optimized the time delay to load and remotely visualize the images. The results were achieved by applying a test procedure called ‘benchmark protocol’. The videoconferencing system used for the test was Intel ProShare 200™ v2.0. The image transfer was performed by a BRI ISDN connection. We showed that the image format had no significant influence on the time delay. We presented an optimal procedure for image transfer. Furthermore, store and forward procedures with simple file transfer were shown to be inferior to the use of application sharing. For radiological image transfer we recommend to use lossless file formats and application sharing with the image already loaded in because this method achieves the lowest time delays.

Desktop videoconferencing performance based on an ATM metropolitan area network

The DIVINE project enables us to evaluate a high-quality desktop videoconferencing system on an ATM network. After presentation of the methodologies and performance measurement tools used, we analyze the QoS of multimedia services implemented on the DIVINE system. Some performance evaluations have been achieved on the OASICE ATM MAN.

FreeWalk: a 3D virtual space for casual meetings

A meeting environment for casual communication in a networked community, FreeWalk provides a 3D common area where everyone can meet and talk freely. FreeWalk represents participants as 3D polygon pyramids, on which their live video is mapped. Voice volume remains proportional to the distance between sender and receiver. For evaluation, we compared communications in FreeWalk to a conventional desktop videoconferencing system and a face-to-face meeting.

Real-time computing with lock-free shared objects

This article considers the use of lock-free shared objects within hard real-time systems. As the name suggests,lock-freeshared objects are distinguished by the fact that they are accessed without locking. As such, they do not give rise to priority inversions, a key advantage over conventional, lock-based object-sharing approaches. Despite this advantage, it is not immediately apparent that lock-free shared objects can be employed if tasks must adhere to strict timing constraints. In particular, lock-free object implementations permit concurrent operations to interfere with each other, and repeated interferences can cause a given operation to take an arbitrarily long time to complete. The main contribution of this article is to show that such interferences can be bounded by judicious scheduling. This work pertains to periodic, hard real-time tasks that share lock-free objects on a uniprocessor. In the first part of the article, scheduling conditions are derived for such tasks, for both static and dynamic priority schemes. Based on these conditions, it is formally shown that lock-free shared objects often incur less overhead than object implementations based on wait-free algorithms or lock-based schemes. In the last part of the article, this conclusion is validated experimentally through work involving a real-time desktop videoconferencing system.

A low complexity H.261-compatible software video decoder

The design of a video decoder suitable for implementation in software is considered, in the context of a desktop videoconferencing system. It is required that the decoder handle bit streams from standard H.261 encoders, in order to facilitate interworking with existing systems. Real-time operation in software is achieved by decoding only the low-frequency components in the bit stream, and producing a decimated image. The problem of minimising the drift incurred in this approach is analysed and solved, and an expression for the mean squared drift error is given. The accuracy of the formulation is confirmed by experiment. In addition, several drift-reducing filters are designed and evaluated.

Mediated collaborative research?

Several countries are currently in the process of planning and implementing advanced network infrastructures in the scientific and education communities. One of the objectives of this action is to facilitate collaborative research. In this paper, we closely examine the feasibility of this objective, by: 1) noting the claims of the proponents of the high speed academic networks 2) circumscribing the notion of collaborative research, 3) examining the current role of communication technologies in collaborative research, 4) identifying the possible obstacles to attaining this objective, and 5) presenting and analyzing a case study of a distributed research group and the implementation of a desktop videoconference system. The results of the case study tend to reinforce and extend previous observations concerning potential implementation difficulties of network technologies. Furthermore, the study suggests that the social dynamics in some collaborative research groups may complicate the introduction of new network technologies and limit their use.

Computer-based multimedia video conferencing system

An affordable system level design of a practically prototyped computer-based desktop video conferencing (DVC) system that is capable of delivering full motion analog audio and video is presented. The DVC system is designed to exchange full motion analog video and audio among conference participants using point-to-point and multipoint communication. It is capable of interfacing directly with a codec for video conferencing in the digital domain. The main advantages of this system are low cost, flexibility, and the ability to share applications in an effective manner. The proposed DVC system has been implemented to support 12 users and one additional video/audio input for viewing external television broadcasts. >