what-when-how
In Depth Tutorials and Information
11.4.5 Confident
In the CONFIDANT scheme [31,32] direct trust values are updated according to
a Beta distribution
Beta
(
α
,
β
), where
α
and
β
represent the total number of unsuc-
cessful and successful interactions, respectively.
DirectTrust
= −
1
CDT
i j
,
i j
,
α
α β
CDT
=∈
(
Beta F
(
))
=
i j
,
i j
,
+
where
F
i,j
=
(
α
,
β
) is initialized to (1, 1).
α
and
β
are updated as below:
α α
=
+
s
,
β β
= + −
(
1
s
)
where
s
indicates the unsuccessful interaction.
In CONFIDANT the
indirecttrust
values are calculated in the same way as the
direct trust values.
= −
IndirectTrust
1
CIT
i j
,
i j
,
ʹ
ʹ
+
ʹ
α
CiT
=
E
(
Beta R
(
))
=
i j
,
i j
,
α
β
where
R
i,j
=
(
α
' > 0,
β
' > 0)is initialized to (0, 0) and then updated as follows:
R
=
R
+
w F
= α β
(
'
,
'
)
i j
,
i j
,
k
k j
,
Note that
w
k
and the threshold trust value
H'
are set statically.
In Reference 31 a new trust scheme is proposed which involves the observation
of the mutual neighbors of both nodes into the trust value computation based on
Heider's theory and introduces a dynamic threshold.
Trust
i,j
= (
s,u
) is initialized to
(1,1) and then updated as below:
∑
=
+
Trust
( ,
s u
)
f Trust Trust
(
)
'
i j
,
i k
,
k j
,
k N
∈
u
= +
u
e s
,
= + −
s
(
1
e
)
=
⇒
=
−
−
Trust
( ,
x y
)
Trust
'
(
x
1
,
y
1
)
k j
,
k j
,
