Sharif Digital Repository

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... 

Traditional security approaches prevented participants of an environment from malicious behavior by closely monitoring every transaction of the network. Such approaches are very costly in modern autonomous systems, besides, they are also impossible to apply in many cases. Trust management mechanisms are developed in order to ensure safe interactions with unknown parties in such open environments. Most trust management mechanisms rely on testimonies of interaction participants as the source of information to estimate a peer’s reputation. The first challenge that arises here is the lack of incentives for providing such information. Even if interaction parties are encouraged to report the... 

A Mobile Ad hoc NETwork (MANET) is a self-configuring network that is formed automatically by a collection of mobile nodes without the help of a fixed infrastructure or centralized management. In recent years, the use of MANETs has been widespread in many applications, including some mission critical applications, and as such security has become one of the major concerns in MANETs. Due to some unique characteristics of MANETs, prevention methods alone are not sufficient to make them secure; therefore, detection should be added as another defense before an attacker can breach the system. In this thesis, we have expressed some well-known and related intrusion detection systems. Besides we have... 

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... 

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... 

One of the security issues in database outsourcing scenario is the correctness of the query results. Correctness verification includes integrity, completeness and freshness of the results. Most of the proposed approaches for correctness verification impose high overhead on the components of the scenario which prevents the scenario to implemented in practical applications. In this thesis, we have proposed a probabilistic approach which imposes acceptable overhead for correctness verification of returned results of service provider. The approach uses the previous behavior of the service provider to calculate a trust value toward it which is used to adjust the imposed overhead. In other words,... 

In decentralized Supply Chains, each member decides based on his own interests. Conflict of interests results in suboptimal decisions and poor performance for entire supply chains, as well seriously harms credibly information sharing across them. In this thesis, coordination of decisions in supply chains in the context of Capacity Procurement problem are studied in different situations in form of three models. In first model, a dyadic supply chain with stochastic demand and exogenous price is investigated by taking various costs into account. PARD and RCRS contracts are designed and proposed in order for coordination of decisions respectively in full and partial information updating... 

Self-organized public key management scheme in mobile ad hoc networks (MANETs) is an inevitable solution to achieve different security services. The aim of such schemes is to find an efficient protocol which makes the node able to obtain the authenticated public key of another node. Public key transmission and verification is achieved using certificate chain or message authentication code, thus it needs other nodes cooperation. It is also notable that in heterogeneous MANETs which include malicious nodes, this method suffers from low throughput and spoofing attack. In this thesis, a novel certificateless, on-demand self-organized public key management scheme is proposed which is based on the... 

This millennium could be named as a world of relationship and connection which these two terms impacts on each of our business and daily life dimensions, in the world of marketing , consumer relationship management (CRM) was the notion that introduced in 1995 and emphasize on the importance of 1 to 1 interaction. wide perspective and golden target of CRM makes this concept more desirable for all organizations which everyone hope to be achieved it and this is a gains of not just more sales but more profit, in fact CRM focused on the emotional interaction between to part of deals and tries to locked the consumer in the system by creation of sentimental dependence in consumer which drives the... 

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... 

The intrinsic properties of Mobile Ad-hoc Networks (MANETs) caused many challenges for these networks. Among these challenges, security is the most important one. Cryptography has many applications as a network securing method. Limitations on memory and processing capability of nodes in an Ad-hoc network makes it almost impossible to use common cryptography algorithms for these networks. Key distribution is the main challenge of cryptography; therefore, it is reasonable to simply the problem of cryptography in an Ad-hoc network to the problem of key distribution. Up to now, different methods are proposed for key distribution in MANETs; each of which has their own weaknesses. For example some... 

Ambient Intelligence is a new paradigm in information technology that creates environments able to detect and respond to users needs, actions, behaviors and feelings. In the presence of interaction conflicts, user trust plays an important role in accepting Ambient Intelligence environments for living, working, etc. Our main hypothesis is that higher conflict density results in a greater loss of trust in mixed-initiative Ambient Intelligence environments. In this thesis, we propose a comprehensive research method for measuring trust in Ambient Intelligence environments using both crowdsourcing and university surveys. We conduct both web-based experiments and physical experiments to gather... 

The goal of this research is to study the effective factors in order to overcome resistance to change. In today’s competitive world, change is the most critical competitive advantage of an organization to adapt to new circumstances. The failure rate of change projets is more than 70% and there are various factors responsible for this high rate. One of the most important factors is resistance to change. In this research, traditional studies of change starting in the 19’s by Kurt Lewin is the strat point, who had initiated the studies of this field with his three-step model. In recent decades, newer models have emerged which in contrast with previous versions, focused on an individual as the... 

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... 

In this research study, the reciprocal relationship between Emergent States and Team Processes has been analyzed in boards of directors, by using case study method with semi-structured interview as the method of data collection and thematic analysis as the method of data analysis. This research was conducted on the companies which are active in Information Technology industries, their size is in the range of SMEs, and have passed the early startup stage and an external investor has joined the board. After thematic analysis, narrating each case’s story, and theoretical analysis on each case, the obtained results are demonstrated with discussion on both cases, introducing a theoretical model,... 

Regarding to the technology development during recent years, many businesses have lost their traditional style and lots of web-based services have emerged. Also, nowadays one of the most attractive business model is platform-based services. Among these, investment industry is not exceptional and crowdfunding platforms are known as new channel of investment. With respect to this fact that investment by itself can help the economic growth in countries and proper status of Iran from investment viewpoint, developing such platforms may facilitate the investment processes. Regarding to the researches, considering the high amount of uncertainty in platforms and investment processes, especially... 

A Spirit of Trust results from Brandom's thirty-year effort to give a pragmatistic reading of Hegel's Phenomenology of Spirit. In A Spirit of Trust, Brandom reformulates Hegel's arguments in the language of contemporary Analytical Philosophy and gives a unique interpretation of Hegel's key concepts. In this Thesis, we will examine one of its key concepts, namely, Trust; We will pursue the following questions: First, What is Trust? And what is its connection to other aspects of Brandom's philosophy? Second, How does Trust help us in overcoming Alienation? Third, Are Confession and Forgiveness, which are the constitutive concepts of Trust, psychologistic or normative? Fourth, What is the... 

Mobile Bank is a service that has emerged for about a decadein Iran. while electronic methods and information technologies are used ininternational markets, in Iran using new technologies in the payment and financial industry is limited to the ATMs and Shetab network services. One of the mainreasons for the lack of tendency in using mobile banks and other electronic paymentmethods is these methods’ security concerns. Therefore, in this research, anattempt has been made to provide a model for technology acceptance in order toexamine the main factors of insecurity among users. As a case study, MellatMobile Bank's application has been evaluated in this research and an attempt hasbeen made to... 

The complexity of today's world has led us to the point where we will have problems in the intellectual and practical fields without relying on the testimony of experts. Maybe if we could measure the validity of the information by our own knowledge, we would definitely choose this option. But social life has made us rely on others to get the beliefs we need. We consider most of the beliefs we acquire in school, universities, in science books, news, debates and television documentaries to be examples of knowledge. We also claim to know a set of beliefs presented to us by experts. We consider experts as reliable people and we rely on them. In the meantime, we know that we have no other reason...