Arrowhead Framework Research Articles

Service Oriented Architecture enabling the 4th Generation of District Heating

The 4th Generation of District Heating (4GDH) is a complex agglomeration of heat providers, distributors, and consumers that must be automatically, continuously managed and coordinated. It is a complex system of systems; a definition which we align to Maier's architecting principles for systems-of-systems as collaborative systems. Wrapped in the idea of system of systems is the reality that the 4GDH systems’ descriptions and specifications are not currently all known. Nonetheless, the transition into the 4GDH is actual. We propose the use of two frameworks to secure a smooth metamorphosis and assure systems’ operation, maintenance, and evolution. The two frameworks are the Arrowhead Framework and the OPTi Framework. The first one enables system integration through Service Oriented Architecture (SOA) and the second one offers the overall system optimization with respect to all stakeholders. This paper uses the Model Based Systems Engineering (MBSE) tool SysML to model a district heating complex's structures and behaviors from the concept level down to the sensors and actuators within a district heating substation where we apply the SOA technology based on the open Arrowhead Framework. We focus on the Arrowhead Framework's core services, i.e. Service Registry, Authorization and Orchestration to clearly describe the interactions between the different service providers and consumers. Going back up from the sensors to the systems, it is clear that SOA is the architecture that will empower the 4GDH.

Inter-Cloud Communication Through Gatekeepers to Support IoT Service Interaction in the Arrowhead Framework

Although we live in the era of Internet of Things (IoT), many issues on system-interoperability are still not tackled at large. There are limitations for ever-growing IoT realms, especially in resource-constrained domains, where low latency is crucial, and local processing power is a scarce resource. Service Oriented Architectures (SOA) provide functional and configuration flexibility in closed communication environments, where security and service-related orchestration issues are controlled within the local network. For automation systems, these SOA-based networks can have core services, such as Service Registry, Orchestration, Authorization, and so on. A set of such core services are defined, implemented and made available through the Arrowhead Framework. Since the Core Services are distributed resources available for all systems that wish to consume them, these networked services can be considered a cloud. As one cloud cannot serve for all, there is a need for such automation system clouds to interact with each other: use the services of one from another. This paper presents a solution for providing inter-Cloud servicing capabilities in the Arrowhead framework by introducing a gatekeeper concept. The main idea is to extend the service discovery functionality outside the boundaries of a single cloud, and solve the security and orchestration issues in a way that fits into the general Arrowhead concept. This paper also introduces the methodology of creating secure connections between service consumers and providers situated in different clouds.

Making system of systems interoperable – The core components of the arrowhead framework

The objective of the Arrowhead Framework is to efficiently support the development, deployment and operation of interconnected, cooperative systems. It is based on the Service Oriented Architecture philosophy. The building elements of the framework are systems that provide and consume services, and cooperate as systems of systems. Some commonly used systems, such as orchestration, authorization or service registry are considered as core. These can be used by any system of systems that follow the guidelines of the Arrowhead Framework.Within the framework, systems – using different information exchange technologies during collaboration – are helped through various approaches. These include the so-called Interoperability Layer, as well as systems and services for translation. Furthermore, one of the main problems of developing such highly interoperable systems is the lack of understanding between various development groups. Adequate development and service documentation methodologies can help to overcome this issue.The design, development and verification methodology for each service, system and system of systems within the Arrowhead Framework supports that these can be implemented, verified, deployed, and run in an interoperable way. This paper presents an overview of the framework together with its core elements – and provides guidelines for the design and deployment of interoperable, Arrowhead-compliant cooperative systems.