By virtue of technology and benefit advantages, cloud computing has increasingly attracted a large number of potential cloud consumers (PCC) plan to migrate the traditional business to the cloud service. However, trust has become one of the most challenging issues that prevent the PCC from adopting cloud services, especially in trustworthy cloud service selection. Besides, due to the diversity and dynamic of quality of service (QoS) in the cloud environment, the existing trust assessment methods based on the single constant value of QoS attribute and the subjective weight assignment are not good enough to provide an effective solution for PCCs to identify and select a trustworthy cloud service among a wide range of functionally-equivalent cloud service providers (CSPs). To address the challenge, a novel assessment and selection framework for trustworthy cloud service, FASTCloud, is proposed in this study. This framework facilitates PCCs to select a trustworthy cloud service based on their actual QoS requirements. In order to accurately and efficiently assess the trust level of cloud services, a QoS-based trust assessment model is proposed. This model represents a trust level assessment method based on the interval multiple attributes with an objective weight assignment method based on the deviation maximization to adaptively determine the trust level of different cloud services provisioned by candidate CSPs. The advantage of the proposed trust level assessment method in time complexity is demonstrated by the performance analysis and comparison. The experimental result of a case study with an open-source dataset shows that the trust model is efficient in cloud service trust assessment and the FASTCloud can effectively help PCCs select a trustworthy cloud service.

翻译：凭借技术优势和效益优势，云计算日益吸引大量潜在云消费者计划将传统业务迁移至云服务。然而，信任已成为阻碍潜在云消费者采用云服务的最具挑战性问题之一，尤其是在可信云服务选择方面。此外，由于云环境中服务质量属性的多样性和动态性，现有基于单一常量QoS属性和主观权重分配的信任评估方法，不足以提供有效方案帮助潜在云消费者从大量功能等效的云服务提供商中识别和选择可信云服务。为解决这一挑战，本研究提出了一种新型可信云服务评估与选择框架FASTCloud。该框架有助于潜在云消费者根据其实际QoS需求选择可信云服务。为准确高效评估云服务的信任等级，提出了一种基于QoS的信任评估模型。该模型采用基于区间多属性的信任等级评估方法，结合基于偏差最大化的客观权重分配方法，自适应确定候选云服务提供商提供的不同云服务的信任等级。通过性能分析与对比，验证了所提信任等级评估方法在时间复杂度上的优势。基于开源数据集的案例实验结果表明，该信任模型在云服务信任评估中具有高效性，且FASTCloud能够有效帮助潜在云消费者选择可信云服务。