Architecture and Implementation of a Trust Model for Pervasive Applications

Collaborative effort to share resources is a significant feature of pervasive computing environments. To achieve secure service discovery and sharing, and to distinguish between malevolent and benevolent entities, trust models must be defined. It is critical to estimate a device\u27s initial trust value because of the transient nature of pervasive smart space; however, most of the prior research work on trust models for pervasive applications used the notion of constant initial trust assignment. In this paper, we design and implement a trust model called DIRT. We categorize services in different security levels and depending on the service requester\u27s context information, we calculate the initial trust value. Our trust value is assigned for each device and for each service. Our overall trust estimation for a service depends on the recommendations of the neighbouring devices, inference from other service-trust values for that device, and direct trust experience. We provide an extensive survey of related work, and we demonstrate the distinguishing features of our proposed model with respect to the existing models. We implement a healthcare-monitoring application and a location-based service prototype over DIRT. We also provide a performance analysis of the model with respect to some of its important characteristics tested in various scenarios

A prototype and demonstrator of Akogrimo’s architecture: An approach of merging grids, SOA, and the mobile Internet

The trend of merging telecommunication infrastructures with traditional Information Technology (IT) infrastructures is ongoing and important for commercial service providers. The driver behind this development is, on one hand, the strong need for enhanced services and on the other hand, the need of telecommunication operators aiming at value-added service provisioning to a wide variety of customers. In the telecommunications sector, the IP Multimedia Subsystem (IMS) is a promising service platform, which may become a ''standard'' for supporting added-value services on top of the next generation network infrastructure. However, since its range of applicability is bound to SIP- enabled services, IMS extensions are being proposed by ''SIPifying'' applications. In parallel to these developments within the traditional IT sector, the notion of Virtual Organizations (VO) enabling collaborative businesses across organizational boundaries is addressed in the framework of Web Services (WS) standards implementing a Service-oriented Architecture (SOA). Here, concepts for controlled resource and service sharing based on WS and Semantic Technologies have been consolidated. Since the telecommunications sector has become, in the meantime ''mobile'', all concepts brought into this infrastructure must cope with the dynamics mobility brings in. Therefore, within the Akogrimo project the VO concept has been extended towards a Mobile Dynamic Virtual Organization (MDVO) concept, additionally considering key requirements of mobile users and resources. Especial attention is given to ensure the duality of the merge of both, SOA and IMS approaches to holistically support SOA-enabled mobile added-value services and their users. This work describes major results of the Akogrimo project, paying special attention to the overall Akogrimo architecture, the prototype implemented, and the key scenario in which the instantiated Akogrimo architecture shows a very clear picture of applicability, use, and an additional functional evaluation

Formulating and managing viable SLAs in cloud computing from a small to medium service provider's viewpoint: A state-of-the-art review

© 2017 Elsevier Ltd In today's competitive world, service providers need to be customer-focused and proactive in their marketing strategies to create consumer awareness of their services. Cloud computing provides an open and ubiquitous computing feature in which a large random number of consumers can interact with providers and request services. In such an environment, there is a need for intelligent and efficient methods that increase confidence in the successful achievement of business requirements. One such method is the Service Level Agreement (SLA), which is comprised of service objectives, business terms, service relations, obligations and the possible action to be taken in the case of SLA violation. Most of the emphasis in the literature has, until now, been on the formation of meaningful SLAs by service consumers, through which their requirements will be met. However, in an increasingly competitive market based on the cloud environment, service providers too need a framework that will form a viable SLA, predict possible SLA violations before they occur, and generate early warning alarms that flag a potential lack of resources. This is because when a provider and a consumer commit to an SLA, the service provider is bound to reserve the agreed amount of resources for the entire period of that agreement – whether the consumer uses them or not. It is therefore very important for cloud providers to accurately predict the likely resource usage for a particular consumer and to formulate an appropriate SLA before finalizing an agreement. This problem is more important for a small to medium cloud service provider which has limited resources that must be utilized in the best possible way to generate maximum revenue. A viable SLA in cloud computing is one that intelligently helps the service provider to determine the amount of resources to offer to a requesting consumer, and there are number of studies on SLA management in the literature. The aim of this paper is two-fold. First, it presents a comprehensive overview of existing state-of-the-art SLA management approaches in cloud computing, and their features and shortcomings in creating viable SLAs from the service provider's viewpoint. From a thorough analysis, we observe that the lack of a viable SLA management framework renders a service provider unable to make wise decisions in forming an SLA, which could lead to service violations and violation penalties. To fill this gap, our second contribution is the proposal of the Optimized Personalized Viable SLA (OPV-SLA) framework which assists a service provider to form a viable SLA and start managing SLA violation before an SLA is formed and executed. The framework also assists a service provider to make an optimal decision in service formation and allocate the appropriate amount of marginal resources. We demonstrate the applicability of our framework in forming viable SLAs through experiments. From the evaluative results, we observe that our framework helps a service provider to form viable SLAs and later to manage them to effectively minimize possible service violation and penalties