الفهرس 
AbstractOnly 14 pages are availabe for public view
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Abstract
Cloud computing has become a common desire as an alternative for investing in new IT systems. Every day, more agencies benefit from the services reachable in the cloud. Due to the large storage of information and data in the cloud, concerns about customer confidence or trust in the cloud increase as cloud services have been increased. Cloud computing provides us with things such as convenience, reduced cost and high scalability. But despite all of these advantages, there are many enterprises, individual users and organizations that still have not deployed this innovative technology. Several reasons lead to this problem; however, the main concerns are related to security, privacy and trust. Low trust between users and cloud computing providers has been found in the literature. It is important to note that choosing cloud computing assumes a high degree of trust between the cloud provider and its cloud user, as the provider will be trusted with sensitive information and safety details. In an attempt to solve the problem and increase the investment and adoption of this technology. The cloud user only needs internet and remote servers in order to use cloud computing services. Cloud computing brings us both opportunities and challenges. Reduced cost, speed of deployment, scalability, less requirements for operating IT functions, and other environmental benefits, such as less physical space, are among the benefits cloud computing provides. The quality and reliability of the services become an important aspect, as customers have no direct influence on the services. Therefore service level agreements are fundamental to effective cloud utilization and especially business customers need them to ensure risks and service qualities are prevented respectively provided in the way they want. For this purpose, the expected service qualities are documented as legally binding in contracts between provider and customer. Due to significant variation in consumer needs, SLAs have to be created individually by a negotiation process. The confirmed SLAs serve as a basis for compliance and monitoring of the QoS. Due to the dynamic cloud character, the QoS attributes must be monitored and managed consistently Given the diversity of cloud service providers, identifying the appropriate cloud services, including trust, which meets organizations’ requirements, is one of the main challenges in cloud computing. To operate and implement the idea of cloud computing, we have to consider how customers are attracted to this technology; it is achieved through customers’ trust in cloud service providers. Therefore, the ranking of trust for both service providers and customers is a critical subject in cloud environments. A framework for ranking trust ratio to cloud service providers is introduced as Gogrid (CSP1), Rackspace (CSP2), Amazon EC2 (CSP3), CLOUD-FLARE (CSP4), Nepho-Scale (CSP5), and Relia-Cloud (CSP6), depending on proposed criteria of agility, finance, performance, security, and usability, and was applied the techniques of FL, AHP, TOPSIS, PROMETHEE II, and VIKOR techniques. Performance and total cost are evaluated based on users’ geographical distribution and data center using the Cloud-Analyst application. Each method was compared with others to choose the preferable one from the customer’s perspective as setting selecting parameters is a priority according to weight on the AHP method. It was identified and concluded that TOPSIS and VIKOR are the best methods for choosing cloud service providers and trust ranking. This thesis’s contribution included modeling the problem of choosing the suitable trust methods for cloud service providers and proposed methods and alternatives suitable for cloud users. It is also a flexible framework that can address many complex issues in selecting service providers to evaluate factors other than trust.