Requirements Engineering

Image Requirements Engineering

Digitalization is leading to significant changes in our environment. This development directly influences our lives and working styles. New requirements for interconnecting also affect existing standards. It is quite clear that new standards and specifications need to be developed to handle interdisciplinary topics. How can we actively influence this transformation?

For the purposes of standardization and specification development, the requirements-engineering method has proven to be a helpful approach to achieving a common understanding of interdisciplinary technologies. This is a method known from software modeling, which analyses potential use cases and determines the resulting cross-system interoperability and IT security requirements. In order to identify gaps in the framework of standards and specifications with the help of use cases, a reference architecture (an idealized model) is also required, which can be used for the implementation and visualization of the interdisciplinary requirements.

The identified data and requirements are then mapped into the relevant standards and specifications.

The use cases and requirements are stored in a Use Case Management Repository. The repository serves as the basis for further standardization work within the DKE.

Requirement engineering for an efficient standardization process on the basis of use case development and analysis

Digitalization changes our environment significantly. This development influences our lives and working styles directly. New requirements for interconnection also affect existing standards. It is quite clear that standards and specifications need to be extended or newly developed to handle cross-system topics.

Which new business need do we have to meet for standardization, to ensure companies and industries to be successful? Beside this most important questions other topics need to be considered: First we need cross-system IT Security and interoperability, next we have to manage close networking of technology and manufacturing, we need an answer for cross-domain issues and last but not least the Internet of Things will change value chains.

All these questions can be concluded into one: How can we actively influence this transformation? How do we bring all necessary inputs together – effectively?

The first barrier is that our experts don't use the same technical terminology because they come from different technical areas.

What do we have to do? We know that all people can tell a story how to do something in a certain manner. Storytelling is a good technique to start collecting intelligence from all different viewpoints. It's the base methodology of the Use Case approach, which is a first step in an overall requirements engineering and management process. User stories are short, simple descriptions of a feature told from the perspective of the or role who desires the new capability, usually a user or customer of the system. The story names also the benefits the new capability is providing. With this methodology we can identify the visions, the ideas and the innovations from a user driven point of view. This is essential for the technical experts to get the right understanding of the market or business needs to be able to design as much as possible usability into the technical solution.

A use case is then the granular, step-by-step decomposition of a user story. A user story can be split into several use cases. Use case can have to view points, a business oriented and a technical or system oriented. The business use case describes the necessary steps of a business workflow, while the system use cases describe the technical implementation to support the business workflow.

Detailing use cases means the collection of a huge amount of information to be exchanged between the actors participating in a certain workflow. By this step we can determine the resulting cross-system interoperability and IT Security requirements.

For better collaborative work, use cases, actors (including roles for business use cases) and requirements should be stored electronically in a use case management repository. DKE had started to develop a use case management repository to store the use cases and requirements. The repository was based on the IEC 62559–2 “Definition of the templates for use cases, actor list and requirements list” developed by IEC System Committee 1 “Smart Energy” / Working Group 5 (former IEC TC8/WG5) “Methodology and tools”. Based on this experience IEC is currently developing a use case repository, which shall be tightly integrated with the other IEC tools to assure consistency in the overall standardization process, e.g. the actor list shall be synchronized with the IEC’s glossary and dictionary or standards referred in the use case description shall be implemented as direct link.

In order to identify gaps in the framework of standards and specifications with the help of use cases, in addition a “reference architecture” is required, which can be used for implementation and visualization of the interdisciplinary requirements. A reference architecture is an idealized model, which should be seen more as a commonly agreed visualization of a technical landscape and note as some kind of architecture dictate. The idea goes back to the Smart Grid Architecture Model (SGAM) framework which had been created by the European Smart Grid Coordination Group. The three dimensional model allows an abstract description towards interoperability (layers), business segments (domains) and integration levels (zones). The interoperability categories define interoperability requirements for different levels, e.g. physical (component layer), communication protocol (communication layer), data models, (information layer), etc. The domain axis can be used to structure business value changes, e.g. the energy supply system into sub-areas, the so called domains. Finally the zone axis can help to define different levels between the pure physical topics, e.g. an electrical transformer and pure IT-driven topics, e.g. energy markets.

Such a model contributes to the common understanding of all stakeholders involved and allows to visualize interactions between the system components to be examined.

Exiting standardized solutions for interaction between the system components can be visualized by this model. New interactions within the systems are described by use cases. The use cases and the identified information can be mapped in the reference architecture model to analyze gaps. The results of gap analysis are input for new projects for standardization organizations and companies.

What is the benefit of use cases and identified requirements? We can provide standards and specifications already in the conceptual phase of new technologies and applications. Furthermore the harmonization of terminology and system architecture visualization allows also to handle cross-domain topics by collaboration of experts from various disciplines.

For further standardization work the use cases and requirements can be stored by the use case management repository and used as starting point for future technologies and the upcoming standardization processes. Over the time the use case repository will contain a comprehensive amount of workflow descriptions form various application areas. This helps for a better mutual understanding between the experts from different disciplines. With the use case management repository, we have created an opportunity to cooperate across borders.

In joint project work, e.g. funded research projects the use case approach has already successfully supported the networking between companies and countries.


Dr. Rolf Apel
Siemens AG
Energy Management Division
Technologiy & Innovation


Jessica Fritz
Project Manager DKE