The capture site is characterised by its repertoire of input devices, and its capture and abstractor objects (lefthand side of Figure). The input devices can be microphones, video cameras, or more singular sensors of various kinds. Sample sensors are pressure sensors, ultrasonic sensors and simple binary on/off sensors (switches). Each input device is tied to a timer controlled object, called a capture object; the timer operates at a sampling rate appropriate for the specific device. Each capture object interfaces with the rest of the system through a circular buffer used to store the most recently captured data. These buffers of the capture objects are available to so-called abstractor objects, doing basic signal processing, accumulations, and comparative analyses (such as history processing). An abstractor object is defined by a specific process performed on one or more (capture or abstractor) objects and possibly the recent history of the abstractor. This recent history is represented by a circular buffer of recent processing results. The data contained in this buffer can be shipped "as is" to the remote sites or used as input to other abstractors.
The display site is characterised by its repertoire of output devices, which are fed by a series of synthesizer objects (see righthand side of Figure). Possible output devices are speakers, displays/projectors, and a whole range of transducers that produce elements of haptic and kinetic response, etc. A sample transducer could be an electromechanical vibrator in the seat or back of a chair or a thermoelectric device to control the heat on parts of a work surface. Incoming messages are dispatched using the message type to a set of synthesizer objects. Each synthesizer object is responsible for a particular abstract representation, i.e., a mapping from presence data to some display method. Typical synthesizer tasks are transformation of the incoming data to fit the dynamic range of the specific display device. Each synthesizer can make use of several different types of data from the remote site and the same data can be delivered to a number of synthesizers.
An important class of synthesizer objects are what we call abstract animations. Our initial intuitions, which were confirmed in our experimentation, suggest that (a) discrete signals are putting higher demands on attention than continuos signals, and (b) that although monotonousness may be low on attention demand it may also be too low and thereby making the signal too easy to ignore. That made us focus on visual display of animated objects, whose dynamic characteristics include moving around in certain patterns and changing appearance in shape, color and size. By tying some dynamic characteristics to presence data and others to simple timers, we are able to create a not-too-monotonous and not-too-abrupt imagery. We are aware that adding dynamics that is unrelated to remote activity may add to the difficulty of interpreting the abstract representations, and we need to study this issue further.
Source: Pedersen, E. R. 1998. People presence or room activity supporting peripheral awareness over distance. In Conference Summary on Human Factors in Computing Systems (CHI’98). ACM Press, 283–284.
http://www.sigchi.org/chi97/proceedings/paper/erp.htm
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