• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.4 no.2
• /
• pp.138-153
• /
• 2010

The interactions between people who do not know each other have been greatly increased with the on-going increase of people's cyberspace activities. In this situation, there exist potential risk factors such as the possibility of fraud, so we need a method to reduce or eliminate those risk factors. Concerning this necessity, rating systems are widely used, and many trust metrics calculated from rate values that people give to each other are proposed to help them make decisions. However, the trust metrics decrease the accuracy, and this is caused by the different rating scales and ranges of each person. So, we propose a fuzzy adjustment method to solve this problem. It is possible to catch the exact meaning of the trust value that each person selects through applying fuzzy sets, which improve the accuracy of the trust metric calculated from the trust values. We have applied our fuzzy adjustment method to the TidalTrust algorithm, a representative algorithm for calculating the local scalar trust metric, and we performed an experimental evaluation with four data sets and three evaluation methods.

• Journal of Convergence for Information Technology
• /
• v.10 no.10
• /
• pp.65-70
• /
• 2020

With the appearance of Bitcoin that builds peer-to-peer networks for transaction of digital content and issuance of cryptocurrency, lots of blockchain networks have been developed to improve transaction performance. Recently, Joseph Lubin discussed Decentralization Transaction per Second (DTPS) against alleviating the value of biased TPS. However, this Lubin's trust model did not enough consider a security issue in scalability trilemma. Accordingly, we proposed a trust metric based on blockchain size, stale block rate, and average block size, using a sigmoid function and convex optimization. Via numerical analysis, we presented the optimal blockchain size of popular blockchain networks and then compared the proposed trust metric with the Lubin's trust model. Besides, Bitcoin based blockchain networks such as Litecoin were superior to Ethereum for trust satisfaction and data volume.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.3 no.4
• /
• pp.366-375
• /
• 2009

In collaborative filtering, many neighbors are needed to improve the quality and stability of the recommendation. The quality may not be good mainly due to the high similarity between two users not guaranteeing the same preference for products considered for recommendation. This paper proposes a consistency definition, rather than similarity, based on information entropy between two users to improve the recommendation. This kind of consistency between two users is then employed as a trust metric in collaborative filtering methods that select neighbors based on the metric. Empirical studies show that such collaborative filtering reduces the number of neighbors required to make the recommendation quality stable. Recommendation quality is also significantly improved.

• Journal of Information Technology Applications and Management
• /
• v.20 no.2
• /
• pp.177-191
• /
• 2013

Social network has been expected to increase the value of social capital through online user interactions which remove geographical boundary. However, online users in social networks face challenges of assessing whether the anonymous user and his/her providing information are reliable or not because of limited experiences with a small number of users. Therefore. it is vital to provide a successful trust model which builds and maintains a web of trust. This study aims to propose a prediction method for the interpersonal trust which measures the level of trust about information provider in Facebook. To develop the prediction method. we first investigated behavioral research for trust in social science and extracted 5 antecedents of trust : lenience, ability, steadiness, intimacy, and similarity. Then we measured the antecedents from the history of interactive behavior and built prediction models using the two decision trees and a computational model. We also applied the proposed method to predict interpersonal trust between Facebook users and evaluated the prediction accuracy. The predicted trust metric has dynamic feature which can be adjusted over time according to the interaction between two users.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.4 no.1
• /
• pp.33-40
• /
• 2008

This paper presents a new scheduling scheme in wireless distributed network. To overcome the limited information about unfamiliar mobile nodes and to reduce the required system performance, we propose a scheduling algorithm of job allocation based on the trust model. The suggested scheduler evaluate an unfamiliar mobile node's trust and make reference to the trust value of neighboring scheduler. This scheduling algorithm can avoid malicious or selfish mobile nodes by assigning low trust values. We also present a trust evaluation metric and show the efficiency of suggested scheduling algorithm by performance evaluation.

• ETRI Journal
• /
• v.27 no.4
• /
• pp.465-468
• /
• 2005

This paper presents a new trust evaluation scheme in an ad hoc network. To overcome the limited information about unfamiliar nodes and to reduce the required memory space, we propose a cluster-based trust evaluation scheme, in which neighboring nodes form a cluster and select one node as a cluster head. The head issues a trust value certificate that can be referred to by its non-neighbor nodes. In this way, an evaluation of an unfamiliar node's trust can be done very efficiently and precisely. In this paper, we present a trust evaluation metric using this scheme and some operations for forming and managing a cluster. An analysis of the proposed scheme over some security problems is also presented.

• Journal of Communications and Networks
• /
• v.18 no.1
• /
• pp.105-111
• /
• 2016

Trust models in the literature of MANETs commonly assume that packets have different security requirements. Before a node forwards a packet, if the recipient's trust level does not meet the packet's requirement level, then the recipient must perform certain security association procedures, such as re-authentication. We present in this paper an analysis of the epidemic broadcast delay in such context. The network, mobility and trust models presented in this paper are quite generic and allow us to obtain the delay component induced only by the security associations along a path. Numerical results obtained by simulations also confirm the accuracy of the analysis. In particular, we can observe from both simulation's and analysis results that, for large and sparsely connected networks, the delay caused by security associations is very small compared to the total delay of a packet. This also means that parameters like network density and nodes' velocity, rather than any trust model parameter, have more impact on the overall delay.

• The KIPS Transactions:PartC
• /
• v.17C no.1
• /
• pp.15-26
• /
• 2010

Social Networks such as 'Facebook' and 'Myspace' are regarded as useful tools for people to share interests and maintain or expand relationships with other people. However, they pose the risk that personal information can be exposed to other people without explicit permission from the information owner. Therefore, we need a solution for this problem. Although existing social network sites allow users to specify the exposing range or users who can access their personal information, this cannot be a practical solution because the information can still be revealed to third parties through the permitted users albeit unintentionally. Usually, people allow the access of unknown person to personal data in online social networks and this implies the possibility of information leakage. We could use an access control method based on trust value, but this has the limitation that it cannot reflect the quantitative risk of information leakage. As a solution to this problem, this paper proposes an access control method based on a synthesized metric from trust and risk factors. Our various experiments show that the risk of information leakage can play an important role in the access control of online social networks.

• Korean Journal of Social Welfare
• /
• v.66 no.1
• /
• pp.333-361
• /
• 2014

By viewing donors for social welfare organization as both givers and beneficiaries, this study aims to address the correlations between the continuity of donors' contributions and enhanced sense of satisfaction as a consequence of participating in donation activities. The predominant concern of this study centers on: (1) the direct effects of individuals' emotional utility, demonstrable utility, trust toward donee organization, self acceptance on the continuation of their donation; (2) the direct effects of individuals' emotional utility, demonstrable utility, trust toward donee organizations on individuals' self-acceptance; (3) the direct effects of individuals' emotional utility, demonstrable utility on their trust toward a donee organization; (4) the indirect effects of individuals' self acceptance on two paths i.e. emotional utility${\rightarrow}$trust${\rightarrow}$self acceptance, and demonstrable utility${\rightarrow}$trust${\rightarrow}$self acceptance; (5) the indirect effects of individuals' individuals' trust toward donee organization on self acceptance on four paths i.e. emotional utility${\rightarrow}$trust${\rightarrow}$continuity of donation; demonstrable utility${\rightarrow}$trust${\rightarrow}$continuity of donation; emotional utility${\rightarrow}$trust${\rightarrow}$self-acceptance, and demonstrable utility${\rightarrow}$trust${\rightarrow}$self-acceptance; (6) the moderating effects of 'financial status' on the causal relationships in the prescribed structural equation model(SEM). In order to verify the moderating effect of 'financial status', multi-group analysis between each of the two groups were conducted. Research is based on a survey among 1116 donors who had made charitable, monetary contributions to social welfare organizations in Daegu and Kyungpook province. Data was collected from 29 organizations. In order to address the research questions, structural equation were employed. A variety of tests are conducted(metric invariance, critical ratio for difference, structural invariance, multi-group analysis, bias-corrected boot-strapping, latent mean analysis including Cohen's effect test).

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.5 no.4
• /
• pp.87-97
• /
• 2009

Internet network routing system is used to prevent spread and distribution of malicious data traffic. This study is based on analysis of diagnostic weakness structure in the network security domain. We propose an improved integrated multi-level protection domain for in the internal route of groupware. This paper's protection domain is designed to handle the malicious data traffic in the groupware and finally leads to lighten the load of data traffic and improve network security in the groupware. Infrastructure of protection domain is transformed into five-stage blocking domain from two or three-stage blocking. Filtering and protections are executed for the entire server at the gateway level and internet traffic route ensures differentiated protection by dividing into five-stage. Five-stage multi-level network security domain's malicious data traffic protection performance is better than former one. In this paper, we use a trust evaluation metric for measuring the security domain's performance and suggested algorithm.