Biomedical Engineering Reference
In-Depth Information
application, and then watch as the collaborator performs the operation. PcAnywhere™ from
Symantec is an example of several of the commercial peer-to-peer collaborative systems that
supports two collaborators through a dedicated Microsoft Windows application that runs on the
workstations involved in the collaboration.
Commercial online conferencing services extend the screen-sharing model by using a third-party
Internet server that can support hundreds of simultaneous users without burdening the host
machine. WebEx™ from WebEx Communications is an example of a browser-based, fee-for-use,
multi-user collaborative system that enables collaborators to share presentations, documents,
applications, voice, and video using Windows, MacOS, or Solaris operating systems.
Both peer-to-peer screen sharing and online conferencing services allow a remote collaborator to see
and interact with a program running on another computer, using either dial-up or high-speed
communications. However, even with a high-bandwidth communications medium, these technologies
don't offer the degree of interaction and level of collaboration possible with an inherently shareable
application. This is in part because screen-sharing programs don't support local video acceleration
hardware to increase 3D rendering speed. In the case of peer-to-peer screen sharing, rendering
speed on the remote workstation is limited by the capabilities of the host machine and the bandwidth
of the connection. The same issues apply to browser-based multi-user systems, with the caveat that
the demands on the host machine are minimized because it only has to communicate with the
commercial server.
The most advanced form of application sharing is to use applications specifically designed as
integrated collaboratories. An example of this level of application sharing is the Chimera molecular
modeling system. The Chimera Collaboratory Extension of the program enables multiple collaborators
to interactively model 3D protein structures in real-time. The Chimera Collaboratory, when combined
with a high-bandwidth communications network, represents the next best thing to working on a
molecule in the same room with collaborators.
The collaborative environments provided by applications such as Chimera are generally superior to
peer-to-peer screen sharing and online conferencing services because of the collaboratory
architecture. For example, each user of Chimera has a separate copy of the application running on
their workstation, as well as a local copy of the modeling data. As a result, each workstation is
responsible for its own rendering and database access, and isn't excessively burdened by having to
send a screen image to a server or another workstation. In addition, Chimera supports the OpenGL
graphics standard, which enables the application to take advantage of local graphics-acceleration
hardware. To avoid chaos when a large number of collaborators are working together in Chimera, one
collaborator is arbitrarily assigned the hub, which the other collaborators can join and leave at will.
The collaborator controlling the hub can pass on authority of controlling a session to another
collaborator at any time.
Application-specific integrated collaboratories are commonly referred to as groupware, which is
typically defined as any software that enables group collaboration over a network. Groupware ranges
from niche applications, such as molecular modeling, programming, and scheduling, to general-
purpose utilities that can support a variety of collaborative activities. These utilities include electronic
whiteboards, shared document libraries, authoring tools, videoconferencing tools, instant messaging,
text forums, and screen sharing.
Electronic whiteboards, which are expressly designed for group collaboration, are virtual whiteboards
that enable multiple collaborators to take turns authoring and modifying hand-drawn or computer-
generated graphics, highlighting points of interest on digital images, or presenting a digitized slide as
part of a presentation. Shared document-authoring tools are designed to enable multiple authors to
create and edit a document online. Text forums are synchronous, text-based systems that allow
group postings of responses to text messages. Most text forums are also asynchronous to the extent
that they are self-archiving. A record of text interchanges is maintained as a database for review by
other collaborators. Related utilities, such as instant messaging, that broadcast or exchange short
text messages, may be used to extend collaboration to users with cell phones and wireless PDAs and
laptops.
