640 W. J. JIANG ET AL.
practices recommended due to (Edieal, Abraham, & Yaniv,
2003; iResearch, 2006; Zhang, Xie, et al., 2011).
For the credibility index accumulation method, some schol-
ars prevent or detect fraud by designing a reliable mechanism
(McCole) (Cripps, Mailath, & Samuelson, 2004; Peng, Lv, &
Hu, 2004; Resnick & Zeckhauser, 2000). Such a mechanism
design can be divided into two types: One mechanism, how
to make the seller truthfully announce and release product
quality and other information, such as List Fee (Zhang, Yang,
& Wang, 2007) mechanism and GWH (Dellarocas, 2003).
Another way is to promote counterparty credit transactions,
such as TTP (Dellarocas, 2002) and RD & TSD mechanism
(Ba, Whinston, & Zhang, 2003). However, these methods still
have some drawbacks, like List Fee and GWH, although it can
prevent sellers to publish false quality information, but cannot
hedge against the fraud buyer; TTP to assume that a third-
party certication body contains information global trading
parties, but there is no such organization, this strategy is not
practical; RD & TSD assume opponents can accurately predict
the auction transaction volume, is expected auction price is
still not yet complex issues to be resolved, so this mechanism
is also dicult to use.
To solve the problem of trust in the credibility of the cur-
rent network online trading mechanism exists, this paper
presents a Online Transactions Dynamic Trust Computing
Model, OTDTC based on a Multi-Agent Systems, established
online auction trust model calculation methods and credibil-
ity achieve the advance prevention, coordinating things aer-
wards punishment trust transaction management mechanism
of three-in-one. e mechanism put forward the concept of
online trading reputation index, users join the network once
the transaction is approved auction on the online auction has
the same reputation, and both parties resolved this problem is
dicult to identify the initial credit. By publishing removed
and blacklist information to other sites, eectively preventing
the members of this network transactions using fraudulent
exit strategy aer the transaction, and then add other sites to
continue fraudulent phenomenon. Meanwhile, network trans-
actions in order to protect their own reputation and earnings
will restrict speculative seller’s fraud, thereby improving net-
work integrity trading mechanism. e use of “credible threat”
concept (Tian & Guo, 2004), OTDTC mechanism constructed
aerwards credible threat of punishment, according to the
theory of repeated games, OTDTC mechanisms in long-term
transactions are eective, research-C2C online auction trust
model to provide some reference and reference.
2. Network transactions trust model based on mas
rough the above analysis of the existing trust model, draw-
ing on the theoretical basis of the results of research on trust,
we combine the characteristics of C2C online transactions,
the establishment of a C2C online auction dynamic trust
computing model. is model includes feedback evaluation,
transaction value, Ratings trust users, time weight, recent
trust, community contribution of six factors (Abdul-Rahman
& Hailes, 2000; Buyya et al., 2011; He, 2010; Jsang, Ismail, &
Boyd, 2007; Lackermair, 2011; Li, 2009, 2010; Marsh, 1994;
Mui, Mohtashemi, & Halberstadt, 2002; Sinclaire et al., 2010;
Tian & Lin, 2007; Xu & Zhang, 2009; Wu et al., 2010; Yaghoubi
et al., 2011; Yu & Munindar, 2002; Zacharia & Maes, 2000;
Zhang, 2010a; Zhang, 2010b; Zimmer et al., 2010; Zhu, 2011).
2.1. Online trading dynamic trust model
Denition 1 Let C={c
1
,c
2
…,c
n
} is the key factors of credit set,
c
i
represents a key factor in the i-th credit, specically auction
items quality or price. For a user u, when the auction transac-
tion is successful, the user v credibility with its trading feedback
to the user u evaluates f(v, u) is c
1
, c
2,
…, c
n
n-dimensional
vector, i.e. f(v, u)=(
c
(v, u),
c
(v, u), …,
c
(v, u)),
c
(v, u) ∈
[-1,1] is the user V to user u is reputation feedback evaluation
scores, When the key factors of credit is c
i
(Jiang, Zhong, Ji, &
Wu, 2011).
Denition 2 Given a user u, set N(u) for user u trading
partners (Jiang, Zhang, & Wang, 2009a).
Denition 3 Given a user u, in [t-1, t] time domain, assum-
ing that x is the user u trading partner, that x∈N(u), t
x
∈[t-1, t]
represents the time that user x and u auction trading, said the
ρ(t
x
, t) is x to u gives reputation feedback evaluation scores of
f(x, u) time discount function.
Denition 4 Given a user u, in [t-1, t] time domain, assum-
ing that x is the user u trading partner, called p(x, u) for the
user x and u the value of the transaction.
Given time t, for user u, its trust computational model is
(Jiang, Zhang & Wang, 2009b; Jiang, Zhong, Zhang & Shi, 2013):
where N(u) is a set of user transactions, i.e. the set of [t − 1,t]
in the time domain, the user u of the user transaction. R
t
rep-
resents t − 1, the user u trust. For N
t
,R
t
represents t − 1, the
user u trust. W[p(x,u)] is the weight function of the transaction
value, which can be written as:
where p(x,u) in [t − 1,t] time domain, the value, which the user
x and u the transaction. μ is the network system (auction) the
minimum value of transactions, the transaction value to meet
the insurance claim.
At present, eBay just for the transaction value of not less than
$200 deal with insurance. According to the 2009 i Research
“China Online Auction Research Report”, now the average
trading price of the auction items traded at around $ 200.
According to this report, we set μ=200, i.e.
[p(x, u)] =
.
Cr[τ
t−1
(x)] is the weight of user trust value x, said the cred-
ibility of the user u transaction object x given feedback evalu-
ation scores of credibility.
ρ(t
x
,t) is the time discounting function, said time weight of
reputation feedback evaluation score, when t
x
leaned closer to
t, the weights are user Agent x to user Agent u gives reputation
feedback evaluation score is higher, we put it into
(t
, t)=𝜌
x
0<ρ<1,which ρ is the time weight factor.
,
is average reputation feedback evaluation scores,
which Agent x score for Agent u, aer the end of the sale,
where, |C| is the base consisting of set of the credibility of the
key factors.
t
(u)=
⎪
⎨
𝛼𝜏
t−1
(u)+𝛽e
k∈N(u)
w[p(x,u)]Cr[𝜏
t−1
(x)]𝜌(t
x
,t
⋅
f (x, u)+𝛾cf (u)) N(u) ≠ 0
𝜏
t−1
(u) N(u)=0
(2)
[p(x, u)] =
(3)
f (x, u)=
i=1
𝜔
ci
f
ci
(x, u)
C
𝜔
c
i
c