Information Technology Reference
In-Depth Information
prevent them to enter limitless circulation. In relation reasoning, it is difficult to
decide whether new constraints are useful for solving given problem. The mark
reasoning can be used in constraint with arbitrary form and thus be much better
than other reasoning.
Existing constraint representation can be classified into several categories
according to complexity, which are listed below:
• Unary predicate
• Order relation language, which only includes partial order relation of real
variable
• Equations similar to "
"
• Linear equation and inequality of unit coefficient, that is all coefficients are - 1,
0, 1
• Linear equation and inequality of arbitrary coefficient
• Boolean combination of constraints
• Algebra and triangular equation
x
-
y
>
c
" or "
x
-
y
≥
c
Compared with several important mark such as symbols, interval and real
number, unary predicate is the most simple constraint.
The partial order relation appears in the systems which only cares about
relations of the quantity. Some systems only care about event order without
considering its time interval, such as NOAH system. In NOAH system,
operations in each level of planning are appointed towards the partial order
relation.
The inequality similar to
is very useful for only knowing the
differences between variables and these inequality constraints are widely used in
TMM and a lot of task planning applications.
In the measure space of scalar multiplication, sometimes it is very useful to
define quotient of two numbers. This kind of expression and difference definition
are isomorphism and the isomorphism mapping is logarithm function. Allen and
Kantz used the Boolean combination of quotient and order relation to implement
the temporal reasoning.
The linear equation with unit coefficient is very useful for commonsense
reasoning because this kind of relation is good enough to describe the
conservation rule in qualitative. Conservation rule affirms the change of value is
equal to the total increased deducts its total decreased values. If we are only
x
-
y
≥
c
