Information Technology Reference
In-Depth Information
importance of manipulation of concrete things in the environment for practical reasoning
has been emphasised by writers on situated cognition (Lave, 1988; Clancey, 1997).
Tokens representing activities often have information about aspects of situations on
them that show the actor the situation they are in. This is best illustrated in the landing
system by the markings on strips. However, even in the landing system the position of
strips relative to each other also shows aspects of situations. Similarly, in the Kanban
system the presence or absence of tokens in various places reveals situations to human
actors in the system. The Cash System partly shows aspects of situations on the white-
board and partly in how much of the compressor has been completed. This is because
the stage of manufacture of the compressor shows part of the situation to the worker.
This parsimonious use of representation is quite consistent with the situated view, in
which a small number of aspects are sufficient to trigger a situated action, but inconsistent
with the deliberative approach.
Structuring the environment of systems is critical to situational activity because without
it repeated actions would not reliably result in goal attainment. This is achieved in two
ways. First, it constrains the possible new situations an actor experiences as a result of
action and this reduces the cognitive burden of choosing alternatives. The structure of
the maze is an example of this. Second, the environmental structure may help reasoning
about activities. Often the palpability of tokens and their physical properties help deliver
both benefits. In the landing system, a controller can position the strips relative to each
other because of the slope and size of the table, thus enabling situation detection and
reasoning about activities. In the Cash System, the partly manufactured machine, by
being its own jig, only permits a restricted range of actions. The Kanban system limits
the quantity of stock circulating by having only a limited number of cards. Workers
can reason about delays in the activity of stock replenishment or in manufacturing by
noticing prolonged absence or presence of Kanban cards in particular places. In addition,
each of these systems requires considerable structuring of the broader environment of
work to make these simple reactive systems work. For instance, the Cash factory is laid
out so that the availability of all relevant part options is directly visible to the foreman
when adding new records to the whiteboard. The need for work environment structuring,
for instance the use of teams and production cells, for the successful implementation of
Kanban is also emphasised in the Just-In-Time literature (Schonberger, 1987).
Tokens, or other parts of environments, also help actors to hand over situations to others.
In the landing system, a controller can hand a strip to another controller because the
controllers are often next to each other. In the Cash compressor system, a half-finished
machine by its very state facilitates a worker in taking over the activity and situation
from another worker.
In the flight landing system not only does the passing of a single strip pass the situation
of a particular flight from one operator to another, but the visible arrangement of all
strips is used to hand over the total flight situation at the change of shift (Mackay et al.,
1998). Similarly, Kanban movements hand over a shortage situation between the multiple
participating actors, while the arrangement on the Kanban board allows the total shortage
situation to be seen by foremen.
Implications for a situational methodology
By examining the systems described above we can draw two groups of implications for
a situational methodology. First, the examples exhibit many characteristics consistent
with the situational theory of agency. Second, there are characteristics that emerge from
Search WWH ::




Custom Search