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Production System Characteristics
Artificial Intelligence
What is a Production System? It consists of
o A set of rules, each consisting of a left side(a pattern)
thatdetermines the applicability of the rule and a right side
that
describes the operation to be performed if the rule is applied.o
One of more knowledge/databases that contain whatever
information is appropriate for the particular task. Some parts
ofthe database may be permanent. Others may be for the
currentproblem only.
o A control strategy that specifies the order in which the rules
will be
compared to the database and a way of resolving the
conflictsthat arise when several rules match to one.
o ARule applier.
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Production Systemso Examples
The Chess Example The Jar Problem A basic production system
language
General Problem Solving architectureso To summarize ( Steps to
solve a problem)
First reduce the problem to a precise statement, that can bedone
by defining the problems State Space.
Searching for a path through the space from Initial to
FinalState.
Model the process of solving the problem as a
ProductionSystem.
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Control Strategies
Artificial Intelligence
Which rule to apply next? More than one rule will have its left
side match the current state.
The first requirement of a good control strategy is that it
causesmotion
The second requirement of a good control strategy is that it
besystematic.o Construct a tree and weigh out the various options
at each step.o This is where BFS and DFS comes into useo Heuristic
Search can also be used
[T
he methods mentioned above will be discussed at a later
stage]
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Production System Characteristics
Artificial Intelligence
Amonotonic production system is a production system in which
theapplication of a rule never prevents the later application of
anotherrule that could also have been applied at the time the first
rule wasselected.
A non monotic production system is one in which this is not
true.
A partially commutative production system is a production
systemwith the property that if the application of a particular
sequence ofrules transforms state x into y, then any permutation of
those rulesthat is allowable, also transforms state x into state
y.
A commutative production system is a production system that is
bothmonotonic & partially commutative.
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Production System Characteristics
Artificial Intelligence
The significance of these categories of production system lies
in therelationship between the categories and appropriate
implementationstrategies.
Ans to statement 2 : For any solvable problem, there exist an
infinite
number of production systems that describe ways to find
solutions.o Some will be more natural or efficient than others.o
Any problem that can be solved by any production system can be
solved by a commutative one, but it may be practically
useless.
Monotonoic Non monotonicPartiallyCommutative
Theorem Proving Robot Navigation
Not PartiallyCommutative
Chemical SynthesisBridge
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Production System Characteristics
Artificial Intelligence
Partially commutative, monotonic production systems are useful
forsolving ignorable problems.
They can implemented without the ability to backtrack to
previousstates, when it is discovered that an incorrect path has
been
followed. They are useful for problems where things do not
change, new things
are created. Non-monotonic, partially commutative systems, are
useful for
problems in which changes occur but an be reversed and in
whichorder of operations is not critical.
Production Systems that are not partially commutative are useful
formany problems in which irreversible changes occur.
