The cloud continuum concept has drawn increasing attention from practitioners, academics, and funding agencies and been adopted progressively. However, the concept remains mired in various definitions with different studies providing contrasting descriptions. Therefore, to understand the concept of cloud continuum and to provide its definition, in this work we conduct a systematic mapping study of the literature investigating the different definitions, how they evolved, and where does the cloud continue. The main outcome of this work is a complete definition that merges all the common aspects of cloud continuum, which enables practitioners and researchers to better understand what cloud continuum is.

Industrial cyber-physical systems rely increasingly on data from Internet-of-Things (IoT) devices and other systems as continuously emerging use cases implement new intelligent features. Edge computing can be seen as an extension of the cloud in close physical proximity, in which some of the typical cloud computing loads are beneficial to run. This article studies data analytics application development for integration of industrial IoT data and composition of application services executed on edge and cloud. A solution is designed to support heterogeneous hardware and run-time platforms, and focuses on the service layer that enables flexible orchestration of data flows and dynamic service compositions. The unified model and system architecture implemented, using the open Arrowhead framework model, is verified through two representative industrial use cases.

Condition monitoring and maintenance of devices and equipment is an important aspect of operating a production facility affecting the availability of production systems. Modern production environments can consist of thousands of devices that each need to be monitored so that maintenance can be performed when necessary to sustain a cost-effective state of production. Today operation and maintenance (O&M) is typically outsourced, and equipment and device manufacturers have also entered the service business. This brings challenges in managing a multitude of different devices using different protocols as well as in the varying needs for utilizing this information in enterprise functions and services. Based on OPC Unified Architecture (UA) a scalable architecture is developed for providing device status information of heterogeneous field devices and sensors to enterprise level applications and services. A proof of concept implementation of this architecture is presented and its envisioned adoption in a mine environment is discussed.

While working in the cloud, the trend is to secure all the resources in order for the applications and systems to operate as efficiently as possible. Huge amounts of resources are wasted on unnecessary utilities and resource-consuming processes, which can rather have a negative effect. Unikernels are the last trend in this direction. We aim to shed light on the motivations, benefits, and issues in unikernels. Our goal is to systematically analyze what made this technology so attractive, identifying the benefits they have attained and the issues encountered in embracing this new technology. We surveyed academic and grey literature by means of the Multivocal Literature Review process, analyzing 590 sources, of which 62 reported motivations, benefits, and issues. The main motivations for adopting unikernels are performance and security, which are also reflected in the benefits reported. In terms of issues, the maturity of the existing frameworks as well as the tool support, are the main challenges that need to be addressed. Given the great potential that unikernels can bring in terms of performance and security, further research is needed to investigate the pros and cons, how to use them, and in which contexts they are beneficial.