A Comprehensive Trust Model for Improved Reliability in Grid

computing and its related technologies will only be adopted by users, if they are confident that their data and privacy are secured and the system is as scalable, robust and reliable as of their own in their places. Trust and reputation systems have been recognized as playing an important role in decision making in the internet. Reputation based systems can be used in grid to improve the reliability of transactions. Reliability is the probability that a process will successfully perform it's prescribed task without failure at a given point of time. Hence ensuring reliable transactions plays a vital role in grid computing. To achieve reliable transactions mutual trust must be established between the initiator and the provider. This paper aims at providing a robust and reliable model by eliminating the feed backs of the entities which are not having any compatibility with it's own evaluation procedure, This model further applies two way test criteria for initiator and provider and also includes new expression for measuring direct trust. I. INTRODUCTION A Grid integrates and coordinates resources and users within different domains. Grid computing is interconnected computer systems where the machines share the resources which are highly heterogeneous. To achieve reliable transactions mutual trust must be established between the initiator and the provider. Trust is measured by using reputation and reputation is the collective opinion of others. Trust can be defined as strong belief in an entity to act dependably, securely and reliably in a specific context. When we say that we trust some one or some one is trust worthy (1), we assume that the probability that he/she will perform an action that is beneficial to us is high. On the other hand when we say some one is un trust worthy we imply that the beneficial probability is very low and detrimental probability is high. According to Abdul-Rahman and Hailes (2), a reputation is the expectation about an entity's behaviour based on information about or observations of its past behaviour. Reputation is what is generally said or believed about a person or thing's character (3). Therefore, reputation is a measure of trustworthiness, in the sense of reliability. Reputation can be the source of building trust. Reputation can be considered as a collective measure of trustworthiness (in the sense of reliability) based on the referrals or feed backs from members in the same community. An individual's subjective trust can be derived from a combination of received referrals and personal experience.