It is necessary to construct an effective trust model to build trust relationship between peers in peer-to-peer (P2P) network and enhance the security and reliability of P2P systems. The current trust models only fo...It is necessary to construct an effective trust model to build trust relationship between peers in peer-to-peer (P2P) network and enhance the security and reliability of P2P systems. The current trust models only focus on the consumers' evaluation to a transaction, which may be abused by malicious peers to exaggerate or slander the provider deliberately. In this paper, we propose a novel trust model based on mutual evaluation, called METrust, to suppress the peers' malicious behavior, such as dishonest evaluation and strategic attack. METrust considers the factors including mutual evaluation, similarity risk, time window, incentive, and punishment mechanism. The trust value is composed of the direct trust value and the recommendation trust value. In order to inhibit dishonest evaluation, both participants should give evaluation information based on peers' own experiences about the transaction while computing the direct trust value. In view of this, the mutual evaluation consistency factor and its time decay function are proposed. Besides, to reduce the risk of computing the recommendation trust based on the recommendations of friend peers, the similarity risk is introduced to measure the uncertainty of the similarity computing, while similarity is used to measure credibility. The experimental results show that METrust is effective, and it has advantages in the inhibition of the various malicious behaviors.展开更多
Based on human psychological cognitive behavior, a Comprehensive and Adaptive Trust (CAT) model for largescale P2P networks is proposed. Firstly, an adaptive trusted decision-making method based on HEW (Historical ...Based on human psychological cognitive behavior, a Comprehensive and Adaptive Trust (CAT) model for largescale P2P networks is proposed. Firstly, an adaptive trusted decision-making method based on HEW (Historical Evidences Window) is proposed, which can not only reduce the risk and improve system efficiency, but also solve the trust forecasting problem when the direct evidences are insufficient. Then, direct trust computing method based on IOWA (Induced Ordered Weighted Averaging) operator and feedback trust converging mechanism based on DTT (Direct Trust Tree) are set up, which makes the model have a better scalability than previous studies. At the same time, two new parameters, confidence factor and feedback factor, are introduced to assign the weights to direct trust and feedback trust adaptively, which overcomes the shortage of traditional method, in which the weights are assigned by subjective ways. Simulation results show that, compared to the existing approaches, the proposed model has remarkable enhancements in the accuracy of trust decision-making and has a better dynamic adaptation capability in handling various dynamic behaviors of peers.展开更多
The recent and unprecedented surge of public interest in peer-to-peer (P2P) file-sharing systems has led to a variety of interesting research questions. How to minimize threats in such an open community is an impor-ta...The recent and unprecedented surge of public interest in peer-to-peer (P2P) file-sharing systems has led to a variety of interesting research questions. How to minimize threats in such an open community is an impor-tant research topic. Trust models have been widely used in estimating the trustworthiness of peers in P2P file-sharing systems where peers can transact with each other without prior experience. However, current P2P trust models almost take no consideration for the nature of trust, fuzzy, complex and dynamic, which results in low efficiency in resisting the attacks of malicious nodes. In this paper, a new trust model named NatureTrust that can alleviate the shortage brought by the nature of trust is proposed. In order to cope with the fuzzy characteristic of trust, linguistic terms are used to express trust. Additionally, fuzzy inference rules are employed to evaluate trust of each transaction so as to handle the complex characteristic of trust. Fur-thermore, risk factor is deployed into NatureTrust to represent and reason with the dynamic characteristic of trust. Both risk and trust factors are considered in evaluating the trustworthiness of each peer. Experimental results show that the trust model analyzed here thus stands against malicious act effectively.展开更多
As one of the most widely accepted adoption models in information systems research, the technology acceptance model (TAM) focuses exclusively on cognition-oriented constructs such as perceived usefulness and perceiv...As one of the most widely accepted adoption models in information systems research, the technology acceptance model (TAM) focuses exclusively on cognition-oriented constructs such as perceived usefulness and perceived ease of use. This perspective may have limited the explanatory power of TAM when it is utilized in studying consumers’ adoption intentions of online shopping. Based on the contrasts between e-commerce systems and traditional workplace information systems as well as empirical findings from a variety of recent e-commerce research works, this paper analyzes an extended model which integrates three additional constructs: trust, social presence, and perceived enjoyment. The interrelationship between these constructs is also explained. Empirical validations of this extended model are expected in future research.展开更多
An electron-addition, under single-crystal conditions, to pentavalent phosphorus compounds as Cl-P (=O, S) Y, Z with the P-Cl bond as electron-accepting group, is selected as an additional model for SN2(P) like reacti...An electron-addition, under single-crystal conditions, to pentavalent phosphorus compounds as Cl-P (=O, S) Y, Z with the P-Cl bond as electron-accepting group, is selected as an additional model for SN2(P) like reactions. It is demonstrated that the geometric information stored in the tetrahedral configuration (substrate) can be transmitted in the corresponding trigonal bipyramidal (TBP) state for nucleophilic substitution. In this article, we focus on these specific mechanistic aspects of carbon and phosphorus. We consider our study as a contribution to the significance of these (bio)chemical intermediates.展开更多
基金supported by National Natural Science Foundation of China (No.60873231)Research Fund for the Doctoral Program of Higher Education (No.20093223120001)+2 种基金Science and Technology Support Program of Jiangsu Province (No.BE2009158)Natural Science Fund of Higher Education of Jiangsu Province(No.09KJB520010)Special Fund for Fast Sharing of Science Paper in Net Era by CSTD (No.2009117)
文摘It is necessary to construct an effective trust model to build trust relationship between peers in peer-to-peer (P2P) network and enhance the security and reliability of P2P systems. The current trust models only focus on the consumers' evaluation to a transaction, which may be abused by malicious peers to exaggerate or slander the provider deliberately. In this paper, we propose a novel trust model based on mutual evaluation, called METrust, to suppress the peers' malicious behavior, such as dishonest evaluation and strategic attack. METrust considers the factors including mutual evaluation, similarity risk, time window, incentive, and punishment mechanism. The trust value is composed of the direct trust value and the recommendation trust value. In order to inhibit dishonest evaluation, both participants should give evaluation information based on peers' own experiences about the transaction while computing the direct trust value. In view of this, the mutual evaluation consistency factor and its time decay function are proposed. Besides, to reduce the risk of computing the recommendation trust based on the recommendations of friend peers, the similarity risk is introduced to measure the uncertainty of the similarity computing, while similarity is used to measure credibility. The experimental results show that METrust is effective, and it has advantages in the inhibition of the various malicious behaviors.
基金supported by the National Natural Science Foundation of China under Grant No.60873071the National High-Tech Research and Development 863 Program of China under Grant No.2008AA01Z410.
文摘Based on human psychological cognitive behavior, a Comprehensive and Adaptive Trust (CAT) model for largescale P2P networks is proposed. Firstly, an adaptive trusted decision-making method based on HEW (Historical Evidences Window) is proposed, which can not only reduce the risk and improve system efficiency, but also solve the trust forecasting problem when the direct evidences are insufficient. Then, direct trust computing method based on IOWA (Induced Ordered Weighted Averaging) operator and feedback trust converging mechanism based on DTT (Direct Trust Tree) are set up, which makes the model have a better scalability than previous studies. At the same time, two new parameters, confidence factor and feedback factor, are introduced to assign the weights to direct trust and feedback trust adaptively, which overcomes the shortage of traditional method, in which the weights are assigned by subjective ways. Simulation results show that, compared to the existing approaches, the proposed model has remarkable enhancements in the accuracy of trust decision-making and has a better dynamic adaptation capability in handling various dynamic behaviors of peers.
文摘The recent and unprecedented surge of public interest in peer-to-peer (P2P) file-sharing systems has led to a variety of interesting research questions. How to minimize threats in such an open community is an impor-tant research topic. Trust models have been widely used in estimating the trustworthiness of peers in P2P file-sharing systems where peers can transact with each other without prior experience. However, current P2P trust models almost take no consideration for the nature of trust, fuzzy, complex and dynamic, which results in low efficiency in resisting the attacks of malicious nodes. In this paper, a new trust model named NatureTrust that can alleviate the shortage brought by the nature of trust is proposed. In order to cope with the fuzzy characteristic of trust, linguistic terms are used to express trust. Additionally, fuzzy inference rules are employed to evaluate trust of each transaction so as to handle the complex characteristic of trust. Fur-thermore, risk factor is deployed into NatureTrust to represent and reason with the dynamic characteristic of trust. Both risk and trust factors are considered in evaluating the trustworthiness of each peer. Experimental results show that the trust model analyzed here thus stands against malicious act effectively.
文摘As one of the most widely accepted adoption models in information systems research, the technology acceptance model (TAM) focuses exclusively on cognition-oriented constructs such as perceived usefulness and perceived ease of use. This perspective may have limited the explanatory power of TAM when it is utilized in studying consumers’ adoption intentions of online shopping. Based on the contrasts between e-commerce systems and traditional workplace information systems as well as empirical findings from a variety of recent e-commerce research works, this paper analyzes an extended model which integrates three additional constructs: trust, social presence, and perceived enjoyment. The interrelationship between these constructs is also explained. Empirical validations of this extended model are expected in future research.
文摘An electron-addition, under single-crystal conditions, to pentavalent phosphorus compounds as Cl-P (=O, S) Y, Z with the P-Cl bond as electron-accepting group, is selected as an additional model for SN2(P) like reactions. It is demonstrated that the geometric information stored in the tetrahedral configuration (substrate) can be transmitted in the corresponding trigonal bipyramidal (TBP) state for nucleophilic substitution. In this article, we focus on these specific mechanistic aspects of carbon and phosphorus. We consider our study as a contribution to the significance of these (bio)chemical intermediates.