Trust Model for Optimized Cloud Services

Cloud computing with its inherent advantages draws attention for business critical applications, but concurrently expects high level of trust in cloud service providers. Reputation-based trust is emerging as a good choice to model trust of cloud service providers based on available evidence. Many existing reputation based systems either ignore or give less importance to uncertainty linked with the evidence. In this paper, we propose an uncertainty model and define our approach to compute opinion for cloud service providers. Using subjective logic operators along with the computed opinion values, we propose mechanisms to calculate the reputation of cloud service providers. We evaluate and compare our proposed model with existing reputation models

Linked USDL Agreement: Effectively Sharing Semantic Service Level Agreements on the Web

As the use of services available on the Web is becoming mainstream, contracts and legal aspects of the relationship between providers and consumers need to be formalized. However, current proposals to model service level agreements are mostly focused on technical aspects, do not explicitly provide semantics to agreement terms, and do not follow Web principles. These limitations prevent take-up, automatic processing, and effective sharing of agreements. Linked USDL Agreement is a Linked Data based semantic model to describe and share service agreements that extends Linked USDL, which offers a family of languages to describe various technical and business aspects of services. We followed a use case driven approach, evaluating the applicability of our proposal in a cloud computing scenario, and comparing its expressiveness with existing models. Finally, we show a concrete tool that helps to model and check the validity of agreements.Junta de Andalucía P12-TIC-1867Ministerio de Economía y Competitividad TIN2012-32273Junta de Andalucía P10-TIC-5906Ministerio de Economía y Competitividad IPT- 2013-0890-

!Agree Studio: a Platform to Edit and Validate Ws-Agreement Documents

The widespread use of SLA-regulated Cloud services, in which the violation of SLA terms may imply a penalty for the parties, have increased the importance and complexity of systems supporting the SLA lifecycle. Although these systems can be very different from each other, ranging from service monitoring platforms to auto-scaling solutions according to SLAs, they all share the need of having machine-processable and semantically valid SLAs. in this paper we present iAgree studio, the first application, up to our knowledge, that is able to edit and semantically validate agreement documents that are compliant with the WS–Agreement specification by checking properties such as its consistency, and the compliance between templates and agreement offers. in addition, it reports explanations when documents are not valid. Moreover, it allows users to combine the validation and explanation operations by means of a scenarios develope

1 A Survey on Service Quality Description

Quality of service (QoS) can be a critical element for achieving the business goals of a service provider, for the acceptance of a service by the user, or for guaranteeing service characteristics in a composition of services, where a service is defined as either a software or a software-support (i.e., infrastructural) service which is available on any type of network or electronic channel. The goal of this article is to compare the approaches to QoS description in the literature, where several models and metamodels are included. consider a large spectrum of models and metamodels to describe service quality, ranging from ontological approaches to define quality measures, metrics, and dimensions, to metamodels enabling the specification of quality-based service requirements and capabilities as well as of SLAs (Service-Level Agreements) and SLA templates for service provisioning. Our survey is performed by inspecting the characteristics of the available approaches to reveal which are the consolidated ones and which are the ones specific to given aspects and to analyze where the need for further research and investigation lies. The approaches here illustrated have been selected based on a systematic review of conference proceedings and journals spanning various research areas in compute