3 research outputs found
Model-Driven Engineering for Analysing, Modelling and Comparing Cloud Computing Service Level Agreements
In cloud computing, service level agreements (SLAs) are critical, and underpin a pay- per-consumption business model. Different cloud providers offer different services (of different qualities) on demand, and their pre-defined SLAs are used both to advertise services and to define contracts with consumers. However, different providers express their SLAs using their own vocabularies, typically defined in terms of their own tech- nologies and unique selling points. This can make it difficult for consumers to compare cloud SLAs systematically and precisely. We propose a modelling framework that pro- vides mechanisms that can be used systematically and semi-automatically to model and compare cloud SLAs and consumer requirements. Using MDE principles and tools, we propose a metamodel for cloud provider SLAs and cloud consumer requirements, and thereafter demonstrate how to use model comparison technology for automating differ- ent matching processes, thus helping consumers to choose between different providers. We also demonstrate how the matching process can be interactively configured to take into account consumer preferences, via weighting models. The resulting framework can thus be used to better automate high-level consumer interactions with disparate cloud computing technology platforms
A Rule-Based Method for Comparison of SLAs in Service-Oriented Computing
Service selection based on non-functional properties (NFP) of services is one of the most important and challenging task in service-oriented computing. NFP are usually described in service-level agreements (SLA). Therefore, the problem of comparison of SLAs arises naturally if there is more than one service with the same desired functionality. SLAs are usually written in a special XML-based format (WS-Agreement, WSLA, RBSLA, etc.). They describe some rules of using the service at the proper level, set the metrics by which that service is measured, and the remedies or penalties in case the agreed-upon levels are not achieved. The paper proposes a method to find differences between SLAs using rule-based knowledge representation and first-order logic-based derivation
Service level agreement specification for IoT application workflow activity deployment, configuration and monitoring
PhD ThesisCurrently, we see the use of the Internet of Things (IoT) within various domains
such as healthcare, smart homes, smart cars, smart-x applications, and smart
cities. The number of applications based on IoT and cloud computing is projected
to increase rapidly over the next few years. IoT-based services must meet
the guaranteed levels of quality of service (QoS) to match users’ expectations.
Ensuring QoS through specifying the QoS constraints using service level agreements
(SLAs) is crucial. Also because of the potentially highly complex nature
of multi-layered IoT applications, lifecycle management (deployment, dynamic
reconfiguration, and monitoring) needs to be automated. To achieve this it is
essential to be able to specify SLAs in a machine-readable format.
currently available SLA specification languages are unable to accommodate
the unique characteristics (interdependency of its multi-layers) of the IoT domain.
Therefore, in this research, we propose a grammar for a syntactical structure
of an SLA specification for IoT. The grammar is based on a proposed conceptual
model that considers the main concepts that can be used to express the requirements
for most common hardware and software components of an IoT application
on an end-to-end basis. We follow the Goal Question Metric (GQM) approach to
evaluate the generality and expressiveness of the proposed grammar by reviewing
its concepts and their predefined lists of vocabularies against two use-cases
with a number of participants whose research interests are mainly related to IoT.
The results of the analysis show that the proposed grammar achieved 91.70% of
its generality goal and 93.43% of its expressiveness goal.
To enhance the process of specifying SLA terms, We then developed a toolkit
for creating SLA specifications for IoT applications. The toolkit is used to simplify
the process of capturing the requirements of IoT applications. We demonstrate
the effectiveness of the toolkit using a remote health monitoring service (RHMS)
use-case as well as applying a user experience measure to evaluate the tool by
applying a questionnaire-oriented approach. We discussed the applicability of our
tool by including it as a core component of two different applications: 1) a contextaware
recommender system for IoT configuration across layers; and 2) a tool for
automatically translating an SLA from JSON to a smart contract, deploying it
on different peer nodes that represent the contractual parties. The smart contract
is able to monitor the created SLA using Blockchain technology. These two
applications are utilized within our proposed SLA management framework for IoT.
Furthermore, we propose a greedy heuristic algorithm to decentralize workflow
activities of an IoT application across Edge and Cloud resources to enhance
response time, cost, energy consumption and network usage. We evaluated the
efficiency of our proposed approach using iFogSim simulator. The performance
analysis shows that the proposed algorithm minimized cost, execution time, networking,
and Cloud energy consumption compared to Cloud-only and edge-ward
placement approaches