42
Relational Distance Definition
Let
DA be a relational description over set A,
DB be a relational description over
set B,
and f : A -> B.
• The structural
error of f for Ri in DA and Si in DB is
E (f) = | Ri °
f - Si | + | Si ° f - Ri |
• The total
error of f with respect to DA and DB is
E(f) = å
E (f)
• The relational
distance GD(DA,DB) is given by
GD(DA,DB) = min
E(f)
i
S
i=1
I
i
S
f : A® B, f 1-1 and onto
-1