Even today, the document-centric approach is still widespread in development. But is this still relevant today? Or is a paradigm shift toward model-based development necessary? In this blog post, I would like to compare the two approaches and introduce SysML. SysML is a modeling language for use in systems engineering.
Document-centric vs. model-based working methods
The document-centric approach creates a diverse set of specifications spread across various documents. Developers work on the documents, not on the product. The image below illustrates this approach.
In my opinion, the document-centric approach has some disadvantages:
- Variety of documents
- Information distributed via documents
- Complex process control (workflows)
- Version management and baselines difficult
- Traceability is hard work
- Lack of transparency about project status
In model-based development, everyone works together on a system model. The data is stored in a database. The model is the focus of development. Specifications, test specifications, and other documents are generated from the model.
Do you speak SysML?
To create a model together, you first need a common language. SysML has become established in systems engineering. This is a graphical modeling language based on UML. The language was developed by the OMG (Object Management Group).
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| Dipl.-Ing. Goran Madzar, Partner, Senior Systems Engineer E-mail: madzar@medtech-ingenieur.de Phone: +49 9131 691 240 |
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Do you need support with the development of your medical device? We're happy to help! MEDtech Ingenieur GmbH offers hardware development, software development, systems engineering, mechanical development, and consulting services from a single source. Contact us. |
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SysML is based on UML. Parts of UML that were too software-focused were omitted from SysML. Since requirements play a very important role in systems engineering, requirements diagrams were added to SysML. The diagram below thus illustrates the relationship between UML and SysML.
SysML is suitable for formal description of:
- Structures
- Behave
- Requirements
SysML provides various diagrams for modeling systems:
Enterprise Architect tool
When talking about modeling tools for UML or SysML, there's one tool you can't ignore: Enterprise Architect from the software manufacturer Sparx Systems. Due to its low licensing costs and extensive feature set, the tool is widely used worldwide and is the de facto standard.
Enterprise Architect can be used to create diagrams. The data is located in the Project Browser. In the Project Browser, the model elements are displayed hierarchically in a tree structure. Model elements can be dragged and dropped from the Project Browser into diagrams and thus displayed. Additional elements and relationships can be dragged into a diagram using the toolbox. It is important to know that diagrams only represent a view of the model. Deleting an element in a diagram does not remove the element from the model. Rather, it is no longer displayed in that diagram. If, on the other hand, you delete an element from the Project Browser, it is removed from the model and therefore from all diagrams.
In addition to modeling, Enterprise Architect also offers many other functionalities.
- Creating documents with your own templates
- Convenient use of traceability
- Extensive import and export options
- Creation of add-ins to extend the tool with your own functionalities
- User and rights management
- Audit trail functionality
The topic of model-based development and SysML is very broad, and therefore I can't cover all aspects in this article. However, I will certainly address and discuss one or two topics in this blog. If you have specific questions, please feel free to contact me directly. I'd be happy to answer your question or address it in one of the next blog posts.
I welcome feedback and would love for you to contact me. Feel free to leave a comment on the article. If you know someone who might also be interested in the blog, I'd be very happy if you would recommend it.
Best regards
Goran Madzar