The graphic depiction of a PERT or CPM chart.
A narrative or story that describes the activities of one or more persons, including information about goals, expectations, actions, and reactions.
This is defined by Hutchins (1995a, 117) as “a configuration of the elements in a medium that can be interpreted as a representation.” Problem solving occurs by successive rerepresentations of the problem (i.e., a representation of the problem) through a series of intermediate representational states into a solution (i.e., a representation of the solution). DCog researchers attempt to make the representational state of a functional system explicit and document how changes to its representational state result in goal-directed problem-solving activity.
This can be seen as encoded information, either as a symbolic abstraction of a thing (classical cognitive science), or as a distributed set of nodes (PDP) that, together, have meaning. According to the representational theory of mind, human brains operate on symbolic representations, or codes. DCog extends this to show how transformations to representations need not be entirely symbolic, but may be enacted through manipulations on physical media that have a representational status (e.g., a navigational chart or a drawing).
A standard operator in a keystroke-level model (KLM), R represents the time a user spends waiting for the computer to respond. Only the time actually spent waiting—beyond any mental preparation time (M)—is included in R. R must be estimated for each computer system modeled.
Representations that have a more-or-less arbitrary structure; for example, a word or a sentence in a natural language. See also analog representations.
propagation of representations
A component of information-processing activity in which sequences of transformations from one representational form (or medium) to another result in information-processing activity. Hutchins claims that “representational states are propagated from one medium to another by bringing the states of the media into coordination with one another” (1995a, 117).
In the cognitive-dimensions framework, the ability to review or test a partially complete structure, to check on progress to date it is important for novices, and becomes less so as one gains experience. Some systems allow only a complete design to be reviewed; others allow a review at any stage.
In cognitive-dimensions analysis, a statement of what is required (in cognitive-dimensions terms) to support a given generic activity. The profile of an activity states for each cognitive dimension whether that dimension is material and, if so, what value it should have (e.g., for modification, viscosity must be low, visibility must be high, etc.).
A programming language made up of conditional statements. If all conditions are satisfied, then action is taken.