Database Reference
In-Depth Information
242
Shusaku Tsumoto
procedure
Exclusive and Negative Rules;
var
L : List;
/*Alist of elementary attribute-value pairs */
begin
L := P
0
;
/* P
0
:Alist of elementary attribute-value pairs given in a database */
while
(L
=
{}
)
do
begin
Select one pair [a
i
= v
j
] from L;
if
([a
i
= v
j
]
A
∩
D
= φ)
then do
/* D: positiveexamples of a target class d */
begin
L
ir
:= L
ir
+[a
i
= v
j
];
* Candidates for PositiveRules*/
if
(κ
[a
i
=v
j
]
(D)=1.0)
then
R
er
:= R
er
∧ [a
i
= v
j
];
/* Include [a
i
= v
j
] into the formula of ExclusiveRule*/
end
L := L − [a
i
= v
j
];
end
Construct NegativeRules:
Take the contrapositiveofR
er
.
end
{Exclusive and Negative Rules};
Fig. 9.8.
Induction of exclusive and negative rules.
procedure
P ositive Rules;
var
i : integer;
M, L
i
: List;
begin
L
1
:= L
ir
;
/* L
ir
:Alist of candidates generated by induction of exclusive rules */
i :=1; M := {};
for
i :=1
to
n
do
/* n: Total number of attributes given
in a database */
begin
while
( L
i
= {} )
do
begin
Select one pair R =
∧
[a
i
= v
j
] from L
i
;
;
if
(α
R
(D) >δ
α
)
then do
S
ir
:= S
ir
+ {R};
/* Include R in a list of the PositiveRules*/
else
M := M + {R};
end
L
i+1
:=(A list of the whole combination of the conjunction formulae in M);
end
end
{P ositive Rules};
L
i
:= L
i
−{
R
}
Fig. 9.9.
Induction of positive rules.
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