# Agile Service Engineering in the Industrial Internet of Things
###### Abstract  
The emerging Industrial Internet of Things (IIoT) will not only leverage new and potentially disruptive business models but will also change the way software applications will be analyzed and designed. Agility is a need in a systematic service engineering as well as a co-design of requirements and architectural artefacts. Functional and non-functional requirements of IT users (in smart manufacturing mostly from the disciplines of mechanical engineering and electrical engineering) need to be mapped to the capabilities and interaction patterns of emerging IIoT service platforms, not to forget the corresponding information models. The capabilities of such platforms are usually described, structured, and formalized by software architects and software engineers. However, their technical descriptions are far away from the thinking and the thematic terms of end-users. This complicates the transition from requirements analysis to system design, and hence the re-use of existing and the design of future platform capabilities. Current software engineering methodologies do not systematically cover these interlinked and two-sided aspects. The article describes in a comprehensive manner how to close this gap with the help of a service-oriented analysis and design methodology entitled SERVUS (also mentioned in ISO 19119 Annex D) and a corresponding Web-based Platform Engineering Information System (PEIS).  
Service-oriented analysis and design; Industrial Internet of Things; Service Engineering 2018 10, 100; doi:10.3390/61010010  
reference architectures that can be implemented with interoperable and interchangeable building blocks\". The German initiative Industrie 4.0 basically complies with these objectives but focuses on industrial production. As a starting point, a Reference Architecture Model Industrie 4.0 (RAMI4.0) was published [3].  
Today, software and service engineering is performed in an agile manner in order to increase flexibility during the software design and development and to have milestones to re-focus the process. However, agility needs to encompass the requirements analysis phase too. The reason is that only in rare cases are the requirements fully available and fixed when software design and developments starts. To the contrary, especially in the domain of factory automation systems, requirements analysis is an agile process including a multi-step dialogue between the user(s), the stakeholders, and the software architects who know about the technological capabilities and constraints, and the project and development managers who may also estimate the effort to realize the expectations of the user [4]. Such an iterative analysis and design process leads to multiple reconsiderations and/or refinements of the user requirements as all parties involved learn from each other. If multiple users of one or even multiple organizations are involved, such dialogues are usually led during requirements analysis workshops facilitated by experienced system analysts or architects, and carried out occasionally by means of Web-based collaborative video conferencing systems.  
This article describes a novel comprehensive methodology called SERVUS that, on the one hand, underpins this process, and on the other hand, accompanies and supports this process by a flexible documentation tool for all analysis and design artefacts in form of a Platform Engineering Information System (PEIS). SERVUS and PEIS explicitly take into account capabilities of IIoT service platforms as well as constraints of underlying production and manufacturing IT architectures, not to forget concerns about privacy and security.