Access Grid

Overview

The Access Grid is an application for remote audio, video and data communication over the Web. It allows users to see and hear eachother, and to share information, such as stills, movies and presentations.

Each physical location at which the Access Grid is used is known as a node; it can be as simple as a single computer with a web-cam and a microphone/headphone headset; or as elaborate as a meeting room with multiple projectors, screens and cameras, and a room-based sound system for unobtrusive audio pick-up and reproduction.

Navigation to other nodes is via virtual venues, which act as lobbies with exits to other nodes or lobbies.

Software

Access Grid (AG) software was developed at the Argonne National Laboratory, and is freely available from here.

It contains the applications for sending and receiving audio and video streams, for shared applications, and for connecting to host venues or other nodes.

As part of the initial software installation process, application for an authentification certificate must be undertaken.

Nodes

As mentioned, a node is the physical location (and hardware) of the place where the Access Grid is used. It can vary from a Personal Interface to the Grid (a PIG), to a full room-based node able to hold perhaps a few dozen people. Each has its own particular hardware needs.

The node location should allow good isolation from outside noise and light, so that conditions are good for receiving, sending and viewing/hearing video and audio. It should be comfortable (meetings can last for hours), and available at all hours, since meetings may be scheduled well outside of normal local working hours.

Hardware

PIG
Computer: most recent machines should be sufficient for running the AG software. Two monitors are useful for separating AG control windows and display/presentation windows.

Camera: web-cams are generally suitable

Audio: a headset unit with microphone and headphones offers greatest ease of use and set-up, since feedback between audio-in and audio-out will be virtually eliminated. Separate speakers and microphone may be used, but care must be taken to avoid feedback.

Room-based node
Computer: depending on the size of the room, one or more computers may be used. Some nodes have separate machines for audio, video and data display; a small room may make do with a single machine.

Display: generally at least one projector and screen, although two or more allow more variety with regard to placement of various control and display windows. It is not likely that the participants will need to see the control windows, so these probably need be visible only to the node operator; thus, any projectors/screens can be dedicated to display windows.

Camera: one or more cameras, providing views of the local participants and perhaps the local screen. More flexibility (and cost) comes with camera mounts which can be rotated remotely, and lenses with remote focus/zoom control.

Audio: more complicated, since feedback and echo become problematic. Some form of hardware/software-based echo cancellation is required. Wide-patterned microphones are preferred for pick-up, and should be located to allow all participants to be heard at comfortable speaking levels. Also, speakers should be located so that all participants can hear remote sites, and local participants, at comfortable listening and speaking levels.

SAPAC AG facilites

Links to useful AG sites