Sharif Digital Repository

Trust management is a new security solution for situations that there is not enough information about the members of a system. As other security solutions, trust management solutions are not secure against attacks and malicious behaviors. Collusion is one of the most destructive malicious behaviors in these systems. Colluders seek to unfairly affect the trust system. Most of the trust models are vulnerable against this malicious behavior or consider only a limited set of collusion scenarios to resist. Some other mitigation approaches are specific to a trust model and cannot be used by other models. One of the methods to implement trust is exploiting reputation. Reputation systems can be... 

People usually use trust and reputation when they encounter uncertainty in the nature. Graphs are good tools to model and analysis of trust’s problems. If we show human and computer agents by graph’s nodes and trust values by its edges, in literature, the output graph is so-called Web of Trust. Most recently, there are three major research areas in which trust is studied. First area is policy-based trust which uses policies, digital signature and authentication methods. Second area is reputation-based trust which uses reputation and social network tools to estimate trust where past interactions or performance for an entity are combined to assess its future behavior. Third area is trust... 

Trust prediction, the ability to identify how much to trust to allocate an unknown user, is an important prerequisite toward the development of scalable on-line e-commerce communities. We are more likely to purchase an item from a seller on an e-commerce websites such as eBay or Amazon, if our trusted acquaintances have reported positive experiences with that seller in the past. Reviews from trusted users will carry more weight towards the purchasing decision than reviews from anonymous or unknown customers. Thus, these platforms must support computational mechanisms for propagating trust between users. One of the significant challenges in the trust prediction problem is the unprecedented... 

With the development of social network sites and wide use of Social Networks, information security and confidence of its components, became more and more important and turned into subject of many studies and researches. Relationship based on trust besides increasing productivity reduces risk of information transmission to non-related people. Although in the real world, semantic relations are the main basics for trust, but the existing methods of trusting in current sites have less attention to this point. To reduce such issues, firstly this research is going to use an added semantic understanding on top of the social networks structure. To do so, there is an inference engine in addition to a... 

One of the main purposes of social networks is to share and exchange information. By rapid growth of social networks in Web and considering that the major part of the interactions occurs between unknown individuals; trust plays an important role in forming the relationship among users. On the other hand, with increase in malicious behavior in online communities, the ability to evaluate the trustworthiness of a person before interacting with him has an important effect on the users’ decisions. Trust inference is an approach to fulfill this requirement. Trust inference mechanism can be described as an algorithm that uses the existing trust relationships between users and propagates trust along... 

Trust as a major part of human interactions, lets us take the risk of decision making in uncertain situations. In computer science trust has lots of applications, and is stated as the highest level in the Semantic Web Cake and one of the seven points of W3C consortium. Trust can be embedded into several different networks and Social networks. Regarding to the fact that rust is transitive and value of trust can be compound and different paths in trust graph has different properties; a trust framework can be formed to embed trust into different networks. This framework should define trust and distrust, certainty and uncertainty, context and trust propagation. Architecture of this general... 

We explain a new trust region algorithm for solving unconstrained optimization problems where the redius update is computed using the model information at the current iterate rather than at the preceding one, recently proposed by Bastin, Malmedy, Mouffe, Toint and Tomanos. Then we discuss a modification mixing the concepts of nonmonotone trust region, line search and internal doubling. We use line search to finds a point that satisfies the Wolfe conditions. After that, we explain a new trust region algorithm for solving unconstrained optimization problems where simultaneously satisfies the quasi-Newton condition at each iteration and maintains a positive-definite approximation to the Hessian... 

Classified ads are one of the first E-Commerce formed after the introduction of the internet to the world which is still popular. Divar is one of the main online classified ads and thousands of transactions are happening daily. The transaction of demandant and supplier happens in a risky relation that needs trust to facilitate this transaction. In this research, we are trying to study trust models in the context of C2C E-commerce. As there are no structural assurance and feedback mechanisms in Divar, we decide to study the initial trust of members due to a lack of information from each other. In this research, we gather data from 385 participants by an online questionnaire. The results show... 

Although electronic banking service has been introduced in Iran for more than a decade، today half of the people who go to the physical bank branches are the ones can do their affairs via e-banking. The banks’ managers attribute the main reason for these unnecessary travels to insufficient trust towards e-banking systems. One of the important tools in this regard is mobile banking which is prevailing around the world، however it has not prevailed enough in Iran. This research has tried to investigate the cognitive and non-cognitive dimensions of trust to mobile banking. The data for this research has been collected from users of mobile bank service who have filled the online research... 

Several studies in the field of performance management have paid attention to the effect of systemic and instrumental factors on the effectiveness of performance management system. However, the impact of communication and relational factors has received less attention. Furthermore, it seems that similar approach has been used in organizations for considering systemic factors in designing performance management systems rather than human factors. The goal of this research was to study the relationship between employees' trust in their manager as an relational variable with the effectiveness of performance management system and to compare this relationship with the relationship between the...