H. M. Vin, P. T. Zellweger, D. C. Swinehart, and P. V. Rangan. Multimedia conferencing in the Etherphone environment. Computer, 24(10):69-79, Oct. 1991.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....i;L 2 S i and individuals, with L indicating the level of membership. We denote the outmost root session as level 0 session. Many conference scenarios contain only two sublevels, subsessions with L = 1 and coteries with L = 2. Coteries permit private subgrouping for brief exchanges ( sidechats ) [36] without requiring its members to leave the larger group context or open a separate multicast group. Neilsen and Mizuno describe a membership algorithm for joining and leaving coteries [21] and Texier and Plouzeau [32] propose object binding algorithms for multiple sessions, however, to date a ....

H. M. Vin, P. T. Zellweger, D. C. Swinehart, and P. V. Rangan. Multimedia conferencing in the Etherphone environment. Computer, 24(10):69--79, Oct. 1991.

....conferencing system intended to provide a variety of Internet services such as video conferencing and low cost videoon demand. It is not based on SIP. A number of tools (e.g. RAT and NeVoT) support multicast light weight conferencing, without explicit signaling support [9] Etherphone [16] is probably one of the earliest systems supporting multimedia conferencing. Most of these work talk about conferencing in general or a specific implementation of a conferencing system. Here, we compare different models and present performance numbers for a real implementation. VIII. CONCLUSION ....

H. M. Vin, P. T. Zellweger, D. C. Swinehart, and P. V. Rangan, "Multimedia conferencing in the Etherphone environment," IEEE Computer, vol. 24, pp. 69--79, Aug. 1991.

....and therefore will use the terms conferencing and collaborative computing interchangeably. 1.1.3. 2 Locality Another fundamental distinction is local face to face computer augmented meetings [Man88, St87a, Nun91] versus remote meetings for which a real time voice and or video channel is required [Cro90, Cra93, Che92, Vin91, Cas92]. These live media may be carried in digital [Cas92, Ell93] or analog [Ara92, Roo88, Ahu88] form. Another contrasting feature is that some remote conferencing systems are designed for inter office collaboration [Roo88, Ara92] while others are for conferences between special meeting rooms [Ell93, ....

....and inter office conferencing. When groupware applications are used among geographically distributed individuals, naturally a voice channel is required to substitute for face to face speech. Typically, audio is supplied either by conventional telephone conference calls, or packet based networks [Vin91, Sc93b, Ell93]. Part of the motivation behind computer enhanced meeting rooms were studies that suggest considerable amount of time is spent in meetings, that the presence of computers in meetings is still quite minimal even though they are used with increasing frequency outside of meetings, and that software ....

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H.M. Vin, P.T. Zellweger, D.C. Swinehart, P.V. Rangan; Multimedia Conferencing in the Etherphone Environment, IEEE Computer, Vol.24, No.10, Oct 1991.

....for complex software [32] 2 This model is only intuitive, rather than a precise taxonometric model. For example, the axis are not necessarily orthogonal. Our use of the model is to focus on three different driving forces in CSCW systems. 3 including the Bellcore Cruiser [18] Xerox Etherphone [39], TeamWorkstation and ClearBoard 1 [26] and DEC Argo [20] can be characterized as desktop videoconferencing systems. These systems are a natural extension of conventional desktop window systems to embrace windows for images, audio streams, video streams, etc. The fundamental extension is the ....

Harrick M. Vin, Polle T. Zellweger, Daniel C. Swinehart, and P. Venkat Rangan. Multimedia conferencing in the etherphone environment. IEEE Computer, 24(10):237---268, October 1991. 20

....a network architecture in such future distributed systems will be significant, because of higher user demands and greater technological advances. One such functionality is real time communication. There will be great demands for teleconferencing software that can correctly process multimedia data [19]. A user may want to send messages to robots that function in real time to accomplish daily chores, or the robots may even communicate automatically among themselves. Consequently, the support of real time communication in a network architecture is vital and is a new challenge in the field of ....

Herrick M. Vin, Polle T. Zellweger, Daniel C. Swinehart, and P. Venkat Rangan. Multimedia Conferencing in the Etherphone Environment. IEEE Computer, 24(10):69--79, October 1991.

....Although this protocol is quite straightforward, the task of finding the address for remote users in the Internet is less so. Early conferencing applications avoided this issue as they were designed for operation within the local area network or for usage among a known collection of users [27][2] 1] Frequently, the set and locale of potential participants were known a priori. However, with the migration of conferencing services out of the local area and into the wide area, finding remote users over the general Internet becomes problematic not only because of the tremendous numbers of ....

H.M. Vin, D.C. Swinehart, P.T. Zellweger, P.V. Rangan, "Multimedia Conferencing in the Etherphone Environment", IEEE Computer, Vol. 24, No. 10, pp. 69-79, Oct 1991.

....can be applied as the system dynamics become more complex. Other related research efforts have concentrated on limited media forms, such as audio, e.g. the Etherphone project [70] which deals with the considerable task of processing voice samples. The Etherphone concept has been extended to video [75] in a multimedia conferencing application, however, the video component is supported as an analog signal. In this chapter, we investigate the performance of maintaining a set of multimedia stubs in a cache which is local to each kiosk. The multimedia stubs are the preliminary parts of the ....

Vin, H.M., P.T. Zellwger, D.C. Swinehart, and P. Venkat Rangan. "Multimedia Conferencing in the Etherphone Environment". Computer, 24(10), October 1991.

....group members conduct informal discussions in the DVE, the common (virtual) artifact frames the discussion and provides a set of domain specific tools manipulating that artifact. Our VPR [31] is a multiperson DVE supporting free form communication in a manner similar to electronic meeting rooms [15, 37] and other virtual environments [1, 5, 12] but is unique in its support for domain specific tools. A VPR world is defined by a collection of objects, with visual representations and behaviors of varying complexity. An object that represents a human participant is called an avatar, which is a ....

Harrick M. Vin, Polle T. Zellweger, Daniel C. Swinehart, and P. Venkat Rangan. Multimedia conferencing in the etherphone environment. IEEE Computer, 24(10):237---268, October 1991.

.... The VPR is a multiperson, distributed virtual environment, intended to support collaboration among human users in a free form communication environment with embedded domain specific tools [26] The VPR supports free form communication in a manner similar to various other electronic meeting rooms [13, 23, 33] and virtual environments [2, 4, 10] It differs from many other virtual environments in that it is designed to be extended with domain specific tools that provide additional application support for the specific problem being addressed by a VPR session. For example, a formal workflow process ....

Harrick M. Vin, Polle T. Zellweger, Daniel C. Swinehart, and P. Venkat Rangan. Multimedia conferencing in the Etherphone environment. IEEE Computer, 24(10):237---268, October 1991.

....soon, however, attention was turned towards applications and systems distributed over networks and involving several hosts. A number of multiparty, distributed multimedia systems have been described in the literature, each with its own merits and limitations. Early ones, like the Etherphone system [79], provide only logical and not physical media integration. Other systems do not support full motion video [64] which requires high bandwidth as well as real time processing. Many systems that are geared towards groupware applications, impose floor control mechanisms where only one user may ....

H. Vin, P. T. Zellweger, D. C. Swinehart, and P. V. Rangan. Multimedia Conferencing in the Etherphone Environment. IEEE Computer, 24(10):69--79, October 1991.

....system. We are influenced by their approach, but intend to embed more environment in the system than is done in Argo. Xerox Etherphone. The Etherphone system is a multimedia system incorporating audio, video, and data in its environment using the Ethernet to integrate various communication media [27]. The Phoenix extension enhances the basic facilities to implement full audio video conferencing. This work is important because of its contribution to system issues in collaborative multimedia systems. Distributed Objects in VR. Funkhouser describes his work on techniques for efficiently ....

Harrick M. Vin, Polle T. Zellweger, Daniel C. Swinehart, and P. Venkat Rangan. Multimedia conferencing in the etherphone environment. IEEE Computer, 24(10):237---268, October 1991.

....playback of stored media requires addressing three basic overheads: 1) fetch, 2) scheduling, and (3) presentation. Unlike with network based media streaming, in workstation based streaming, playback overheads (1,2,3) are additive and inter dependent. Research in networkbased streaming, such as [31, 45, 74, 90, 103], relies on adaptive scheduling protocols to manage (bounded) network variability. Their focus is on management of overheads up to the delivery of data to the presentation workstation. These approaches assume processing and presentation on the client workstation incur negligible overheads. Since ....

H.M. Vin, P.T. Zellweger, D.C. Swinehart, and P. Venkat Rangan. Multimedia conferencing in the etherphone environment. Computer, 24(10):69--8, October 1991.

.... advances in computing and communication networks in recent years, we have seen the emergence of a variety of distributed multimedia applications[7, 22] Examples of such applications include Computer Supported Cooperative Work (CSCW) 11] medical applications[9] multimedia conferencing[19, 21], and distance education[20] Although most research in this area centers on individual multimedia applications on stand alone hardware, great potential for multimedia computing lies in the widespread development and use of distributed multimedia applications on top of a common platform or system ....

....an Applications Programming Interface. The API makes available various network provided capabilities, and core services to a large class of multimedia applications. Related research includes Xerox PARC s work on the software for the Etherphone system[23] and later extensions to include video[21]. Their software architecture is object based with negotiation among peer objects, but they focus on a single powerful desk top conferencing application, rather than on providing an open platform that supports multiple applications with their own individual policies and requirements. The ....

Vin, H.V., Zellweger, P.T., Swinehart, D.C., and Rangan, P.V., "Multimedia Conferencing in the Etherphone Environment," IEEE Computer, Vol. 24, No. 10, pp. 69--79, October 1991.

....control information not only remotely among peer connection managers, but also among other local conference related components as depicted in Figure 6. Our current teleconferencing system is the forerunner to this architecture, but we have also drawn ideas from other connection management schemes [2, 18, 22, 24, 40]. While these schemes are diverse, each has suggested the need for a connection management abstraction. User Interface Participants: Eve, Steve, and Joe Audio: high qual Video: adequate qual Speed: moderate Cost: moderate . User Interface Reliable Multicast Protocol Connection Control ....

....teleconferences, and (iii) a widely dispersed user population. Assessment of the problem space reveals that, among other needs, a scalable teleconferencing architecture requires a range of session control schemes. A variety of researchers have explored frameworks for well contained conferences [1, 2, 7, 8, 14, 18, 21, 22, 31, 37, 40]. In this tightly controlled model, complete session information is actively shared among and consistently maintained by all conference participants. Participants receive appraisal of who else is involved, acknowledgment that conference state information is current and that communication is ....

Vin, H.M., Swinehart, D.C., Zellweger, P.T., Rangan, V., "Multimedia Conferencing in the Etherphone Environment", IEEE Computer, Vol.24, No.10, pp.69-79 (Oct 1991).

....of the first projects to introduce the concept of a session abstraction with specification of associated session policies. The session is implemented in a centralized fashion; thus, policies related to consistency of the shared state were not required. The Rapport system [4] the Etherphone system [5], the BERKOM system [6] and similar multimedia conferencing system have not focused on issues related to specification of session policy. They tend to use a fixed call model to realize the communications abstraction they offer to a participant. MMCC [7] and IVS [8] are both designed to run over ....

H.M. Vin, D.C. Swinehart, P.T. Zellweger, P.V. Rangan, "Multimedia Conferencing in the Etherphone Environment," IEEE Computer, Vol. 24, No. 10, pp. 69-79, Oct. 1991.

....of the first projects to introduce the concept of a session abstraction with specification of associated session policies. The session is implemented in a centralized fashion; thus, policies related to consistency of the shared state were not required. The Rapport system [4] the Etherphone system [5], the BERKOM system [6] and similar multimedia conferencing system have not focused on issues related to specification of session policy. They tend to use a fixed call model to realize the communications abstraction they offer to a participant. MMCC [7] and IVS [8] are both designed to run over ....

H.M. Vin, D.C. Swinehart, P.T. Zellweger, P.V. Rangan, "Multimedia Conferencing in the Etherphone Environment," IEEE Computer, Vol. 24, No. 10, pp. 69-79, Oct. 1991.

.... The VPR is a multiperson, distributed virtual environment, intended to support collaboration among human users in a free form communi1 cation environment with embedded domainspecific tools [22] The VPR supports free form communication in a manner similar to various other electronic meeting rooms [8, 20, 28] and virtual environments [1, 3, 5] It differs from many other virtual environments in that it is designed to be extended with domain specific tools that provide additional application support for the specific problem being addressed by a VPR session. For example, a formal workflow process ....

Harrick M. Vin, Polle T. Zellweger, Daniel C. Swinehart, and P. Venkat Rangan. Multimedia conferencing in the Etherphone environment. IEEE Computer, 24(10):237---268, October 1991.

....applications. A prime example is video distribution [24, 14] as in cable television systems where a single source generates video (and associated audio) distributed to a large set of receivers who generally have little or no interaction with the source. Another application is video conferencing [2, 10, 28], where each member is both a source and receiver. This application would require a separate MMC per source to support base level audio video distribution. However, video conferencing also requires other control mechanisms which are outside the scope of what is provided by the MMC. More generally, ....

H.M. Vin, P.T. Zellweger, D.C. Swinehart, and P.V. Rangan, "Multimedia conferencing in the Etherphone environment," IEEE Computer, Vol. 24, No. 10, pp. 69--79, October 1991.

....management offered as part of a teleservice. ffl Multimedia Mailing Systems are an advanced form of electronic mailing systems which integrate various applications like multimedia editing and voice mail. Related projects for example are the voice mailing system Etherphone developed at Xerox PARC [Vin91] the MICE (Modular Integrated Communications Environment) project of Bellcore, and the multimedia mail and archive projects of BERKOM (e.g. TRR94] This type of communication environments may significantly benefit from the availability of a multimedia storage system which serves as a ....

H. M. Vin. Multimedia Conferencing in the Etherphone Environment. IEEE Computer, 24(10):69--79, October 1991.

....Users conference Locality Simultaneity Figure 2. Axes of Scale: Current Teleconferencing Architectures Real time teleconferencing systems, such as Etherphone Phoenixphone, the CAR project and various CoDesk applications, support digital media over a LAN with centralized conference management (CM) [26, 31, 14, 11]. In contrast, the Touring Machine and Rapport represent a class of systems that combine analog media with centralized computer based session control [2, 1] In both cases, concurrency is supported, but only as much as the media crossbar switches or the LANs can physically support. To approximate ....

....discuss the integration of multicast addressing and directory services into our model, and elaborate on additional techniques for bandwidth reduction and heterogeneity. 3. 1 A Scalable Session Model and Its Protocols A variety of researchers have explored frameworks for well contained conferences [1, 2, 5, 6, 10, 13, 16, 17, 22, 26, 31]; in this tightly controlled model, complete session information is actively shared among and consistently maintained by all conference participants. Participants receive appraisal of who else is involved, acknowledgment that conference state information is current and that communication is ....

Vin, H.M., Zellweger, P.T., Swinehart, D.C., Rangan, P.V., "Multimedia Conferencing in the Etherphone Environment", IEEE Computer, Vol.24, No.10 (Oct 1991).

....A prime example is video distribution [GM91, Sinc90] as in Cable Television systems where a single source generates video (and associated audio) distributed to a large set of receivers who generally have little or no interaction with the source. Another application is video conferencing [Casn90, Enso88, VZSR91], where each member is both a source and receiver, and would require one of our Channels per source to support base level audio video distribution. However, video conferencing also requires other control mechanisms which are outside the scope of what is provided by the Channel. More generally, ....

H. M. Vin, P. T. Zellweger, D. C. Swinehart, and P. V. Rangan, "Multimedia conferencing in the Etherphone environment," IEEE Computer, vol. 24, no. 10, pp. 69-79, October 1991.

....peer components at all sites. No particular protocol need be required, so media agents can select the protocol best suited to their needs. Discussion is underway to create a specification for a connection control protocol that could interoperate with other conference manager implementations [1, 18, 19, 29]. The architecture also needs to support an interface for groupware tool builders. Shared applications should be able to link into the system easily (e.g. gain access to participant lists and state information) 10.3 Extensions to the Connection Control Protocol There is the ever present goal ....

Vin, H.M., Swinehart, D.C., Zellweger, P.T., Rangan, V., "Multimedia Conferencing in the Etherphone Environment", Department of Computer Science and Engineering, University of California, San Diego, Technical Report Number CS91-190 (Jan 1991).

No context found.

H. M. Vin, P. T. Zellweger, D. C. Swinehart, and P. V. Rangan. Multimedia conferencing in the Etherphone environment. Computer, 24(10):69-79, Oct. 1991.

No context found.

Herrick M. Vin, Polle T. Zellweger, Daniel C. Swinehart, and P. Venkat Rangan. Multimedia Conferencing in the Etherphone Environment. IEEE Computer, 24(10):69--79, October 1991.

No context found.

Vin HM, Zellweger PT, Swinehart DC, Rangan PV (1991) Multimedia conferencing in the etherphone environment. IEEE Computer 24: 109--119

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