Civil Engineering Reference
In-Depth Information
Gas
Insulated
Airblast
NOC
Notices/
Locks
System State
Certificates
Circuit
Breakers
Check Open
Lock & Caution
Location
Isolation
Wokingham
Open Lock &
Caution
Shutters
Control
Engineer
Switching
Time
Instructions
Accept
Dressed
Rear
Procedures
Log Sheet
Refuse
Switching
Log
Displays
Earth
Switches
Isolators
Front
WE1000
Points of
Isolation
Open
Circuits
Busbar
Closed
Voltage
Electrical
Contacts
Current
Phone
Equipment
Lables
DBI
Indication
Switching
Phone
Faulty
Substations
Identity
SAP
FIGURE 36.1 Propositional network for energy distribution scenario. (Source: Salmon, P. M., Stanton, N. A., and
Walker, G. (2004c). Work Package 1.1.3: NGT Switching Scenario Report. Defence Technology Centre for Human
Factors Integation Report.)
question (moving from left to right across the decomposition hierarchy is the equivalent of zooming
into the system). An ADS can be used to develop so-called problem solving trajectories (Vicente, 1999)
for tasks. Problem solving trajectories demonstrate how actors switch between different models of a
particular work system in order to match their task demands. For example, Vicente (1999) describes
how verbal protocol analysis (VPA) data of electronic technicians engaged in troubleshooting computer
equipment were mapped onto an ADS in order to indicate the different ways (e.g. abstractions and
decompositions) in which technicians were thinking about the work domain. An example of a task
problem solving trajectory for a rail signaling task is presented in Figure 36.2 (Walker and Stanton,
2004). Each component task step was mapped onto an ADS to demonstrate how the platform staff and
signaler were thinking about the system when performing each task.
Task list for rail signaler task:
1. Platform staff have train for detachment
2. Platform staff call signal box
3. Signaler states who they are
4. Platform staff state who they are and location
5. Platform staff justify why line was requested
6. Platform staff state which line is to be blocked
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