Allan Boyd at the Safety Engineering Unit at the University of Aberdeen
is studying Human Reliability Analysis (HRA). HRA is about applying techniques
from human factors, cognitive science, and risk assessment in an attempt
to: produce reasonable assessments of when someone is likely to make a mistake,
discover ways of reducing the likelihood of mistakes being made, provide
ways to mitigate against the consequences of mistakes. At the moment the
research is focusing on the ovenman. The ovenman is a software simulation
that will compare and contrast different HRA techniques/models that are
currently in use throughout industry.
The Safety Engineering Unit
Studies Human Reliability
with the Ovenman, C++ and Amzi!
The ovenman's principle task is to change uncooked cakes into correctly
cooked cakes. A correctly cooked cake is a cake which is not overcooked
or undercooked. To achieve this task the ovenman must prepare a plan of
oven settings that will cause the oven to turn out the current batch of
cakes correctly cooked. A plan is necessary because the available oven
settings cannot usually be made to correspond exactly to the associated
cooking time and cooking temperature of the cakes. An added complication
is provided by the variability of the cake mixtures and the ovenman's
'fuzzy' knowledge of the cooking times and temperatures of the cakes.
There are no written instructions detailing how a type of cake should
be cooked. The ovenman relies purely on his expert knowledge to judge
the appropriate oven settings and the condition of the cakes when viewed
through the oven inspection ports.
The ovenman is not supposed to be a robot who does everything perfectly
all of the time. He is supposed to be more human and as such he is expected
to make mistakes. HRA techniques used in this study are designed to quantify
the likelihood of a mistake being made. In theory then, all that has to
be done to make a 'human' out of the ovenman is to apply an HRA technique
to the model to predict the errors he will make. In effect the HRA technique
dictates the behaviour (or divergence from optimum performance) of the
The ovenroom and its contents and the main driver module are programmed
in C++ for its object orientedness and diversability. The ovenman is programmed
using Amzi! Prolog and controls the ovenman's diagnosis of the situation,
selection of appropriate action i.e. what to do next, and execution of
the action. Prolog was chosen for its built-in inference engine and Amzi!
because of the ease with which their Prolog can be integrated with C++
Safety Engineering Unit
University of Aberdeen
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