Arcticus Systems (Sweden)

Cloud computing and Internet of Things (IoT) are computing technologies that provide services to consumers and businesses, allowing organizations to become more agile and flexible. The potential business values that cloud consumers can achieve depend a lot on the quality of service in the provided cloud services. Therefore, ensuring the quality of service through service-level agreements (SLA) for such cloud-based services is crucial for both the service providers and service consumers. As SLA is critical for cloud deployments and wider adoption of cloud services, the management of SLA in cloud and IoT has thus become an important and essential issue. In this paper we provide an understanding of the current status and maturity level of SLA management in industrial IoT and academic efforts in this field. We also conduct a preliminary survey of current research on SLA management in order to identify open challenges and gaps that need to be addressed in future research directions. In particular, we investigate how to provide useful SLA management support adapted to the maturity level and current industrial practices, and shorten the gap between academia and industry.

A majority of multi-rate real-time systems are constrained by a multitude of timing requirements, in addition to the traditional deadlines on well-studied response times. This means, the timing predictability of these systems not only depends on the schedulability of certain task sets but also on the timely propagation of data through the chains of tasks from sensors to actuators. In the automotive industry, four different timing constraints corresponding to various data propagation delays are commonly specified on the systems. This paper identifies and addresses the source of pessimism as well as optimism in the calculations for one such delay, namely the reaction delay, in the state-of-the-art analysis that is already implemented in several industrial tools. Furthermore, a generic framework is proposed to compute all the four end-to-end data propagation delays, complying with the established delay semantics, in a scheduler and hardware-agnostic manner. This allows analysis of the system models already at early development phases, where limited system information is present. The paper further introduces mechanisms to generate job-level dependencies, a partial ordering of jobs, which need to be satisfied by any execution platform in order to meet the data propagation timing requirements. The job-level dependencies are first added to all task chains of the system and then reduced to its minimum required set such that the job order is not affected. Moreover, a necessary schedulability test is provided, allowing for varying the number of CPUs. The experimental evaluations demonstrate the tightness in the reaction delay with the proposed framework as compared to the existing state-of-the-art and practice solutions.

Model and component-based development approaches have emerged as an attractive option to deal with the complexity of vehicle software. Using these approaches, we provide a method to estimate and refine end-to-end timing requirements in vehicular distributed embedded systems that are developed by reusing the models of legacy systems. This method leverages on the early end-to-end timing analysis that can be performed at the highest abstraction level during the development of these systems. As a proof of concept, we conduct a vehicular-application case study to show the process of estimating and refining the timing requirements early during the development. The case study is modeled with the Rubus-ICE tool suite that is used for the software development of vehicular embedded systems by several international companies.

There is a plethora of models, techniques and tools that support model-and component-based software development of vehicular distributed embedded systems. However, a large majority of them have a limited or no support to model and specify end-to-end resource reservations on the software architectures of these systems. Resource reservations allow flexibility during the development and execution of such complex systems without jeopardizing their predictable behavior. As a result, several applications in the system that share the same hardware platform can be developed independently. In this paper we identify several requirements that any existing component model should fulfill in order to support the modeling of end-to-end resource reservations on the software architectures of such systems. As a proof of concept, we extend the Rubus Component Model (RCM) by fulfilling these requirements. RCM is used for the development of control functionality in vehicular embedded systems by several international companies. We also provide a technique to extract execution models from the software architectures of these systems with resource reservations. In order to show the usability of our technique, we model a vehicular distributed embedded system with the extended component model and extract the execution model from the software architecture augmented with end-to-end resource reservations.

In order to support the end-to-end timing analysis at various abstraction levels and development phases, the end-to-end timing models should be extracted from models of the applications in such a way that they are interoperable. We discuss the challenges and issues that are faced when the timing models are extracted at various abstraction levels during model-and component-based development of vehicular distributed embedded systems. We also present preliminary guidelines and solutions to address these challenges.

Model-based development of software architecture for real-time embedded systems in modern vehicles has had a surge in the last few years. While the introduction of models into the development of real-time embedded systems has increased efficiency in some parts of the engineering process, the models are also cause of novel concerns. In particular, mismatch between structural and semantic assumptions in modeling languages used in different parts of the design process of such systems cause large problems when design artifacts are transformed between modeling languages.

In this paper we discuss the problem of tracing event chains (distributed transactions) while extracting an end-to-end timing model from an existing industrial component model, the Rubus Component Model (RCM). RCM supports component-based development of distributed embedded and real-time systems. The purpose of extracting an end-to-end timing model is to perform the holistic response-time analysis of component-based distributed real-time applications modeled with RCM. We present a solution for RCM by introducing special purpose generic components to it. We believe that the solution is also suitable for other component models that use a pipe-and-filter style for component interconnection.