“Thank you for making a simple door very happy.”
Douglas Adams redefined the Science Fiction genre with his novel “The Hitchhiker’s Guide to the Galaxy” and with his many eccentric ideas. In the five books of this four-part trilogy, the reader encounters talking doors, Marvin, the manic-depressive robot, the Heart of Gold with its Infinite Improbability Drive and the Babelfish, known also to non-readers of the novels because of the translation application of the same name formerly included in the Yahoo! search engine (later to be replaced by Bing Translator).
Sure, it still is Science Fiction, but a lot of it also sounds strangely familiar, with Industry 4.0 being promoted heavily by governments, and the “Internet of Things” becoming a part of our everyday life. Your mobile phone recognizes and processes spoken language. You send short messages from your car. Your coffee machine activates automatically and doors will be able to tell whether you really want to go through them. How does all this function? The answer lies in the system context.
A Door with a Mindset
It probably has happened to you: You pass an automatic door; it opens although you never intended to go inside. The door makes use of motion sensor technology set to a certain radius around the door. If motion is detected inside a defined radius, the door opens. What this sensor is not capable of is interpreting your movements. Humans (and animals) assess whether you really want to go through the door by factoring in the direction you are heading and the speed you are going by.
Another problem with automatic doors is that they very often respond too slowly. A common sight in front of shops is that of customers waving about in order to get the door to open.
What Douglas Adams described in his novels was a future beyond algorithms. Things have a consciousness. “Thank you for making a simple door very happy.” The door is grateful for being able to follow its destination. We’re not there yet, but there is a growing trend for things being online. Estimates put the number of connected everyday objects at 37 billion.¹
Even today, washing machines can be controlled remotely. In the future, the stereo in your car will select your favorite station on its own, know your typical journey to work and suggest alternate routes in case of traffic. The Fraunhofer Application Center Industrial Automation (INA) is currently experimenting with manufacturing facilities including work pieces that tell where they need to be transported and how they are processed further.² And Japanese researchers indeed are working on intelligent sensors for supermarket doors.³
The System Context
How does the system context fit into all this, and why is it so important? Imagine you want to develop a new system, e.g. an automatic door. The door interacts with a motion sensor and one or more motors that open or close the door. The motion sensor accesses an external processing unit that determines the direction and the speed of an object. Maybe there is a counter that recognizes the number of persons passing the door. In Germany the norm DIN 18650 „Schlösser und Baubeschläge – Automatische Türsysteme“ regulates requirements and test procedures for automatic doors, so it needs to be considered when developing the system.
Possibly you do not want to link the counter to the cash system because you consider it as negligible to open the register only in case customers are in the sales area. By determining the system context you determine which aspects you want to consider in the development. Thus, the system context is the part of a system that is absolutely crucial for defining and understanding the system’s requirements.
Visualizing Systems with System Context Diagrams
System Context Diagrams are a powerful of visualizing all elements important for the development of your system. An example follows below, albeit an abstract one. Be advised that from now on you will for all time associate fried eggs with system context.
The egg yolk is the system, and the edge of the egg yolk is the system border. It demarcates the planned system from its environment, i.e. the modifiable part of your development from the aspects on which you have no influence in the development process.
The white of the egg is the system context. The system context border demarcates the relevant part of the environment from the irrelevant part, i.e. the part that has no impact on the requirements of your system.
Of course in reality there are gray areas, e.g. interfaces. Is the register part of the system if linked to the door, or is the cash system not part of your system because you only provide the necessary interface? Gray areas like these can also be found at the system context border, for example if you are unsure whether a norm is relevant for your system or not.
The Major Benefit of System Context Diagrams
There are a number of tools that help you depict the system context in an accessible way, like this:
The right tool makes creating system context diagrams and the use of all elements included easy.
So what are the benefits of system context diagrams? It is the common understanding of the system and its borders. Your entire development team will profit from working with system context diagrams, because you will not waste time trying to realize requirements that are not even part of the system or the context. Still, you will gather and record aspects outside the context because it is the only way to be sure you do not waste time concerning yourself with the same irrelevant aspects time and again. You safe time, money and effort because it is clear right from the onset what you need to be focused on and what you must keep in mind. From this, not only you yourself will benefit, but your entire team, your development and your project.
Douglas Adams was in many ways far ahead of his time, and Industry 4.0 and the Internet of Things still have a long way to go. Still, the amount of interconnectedness and the number of intelligent devices will increase; luckily, the system context and system context diagrams enable you to visualize the structures that are vital for your product development. And if you encounter one of these fancy new automatic doors, why not say Thank You, just in case.
List of references and hints:
 Connected Reality: Die Superkonvergenz unserer Welt. http://www.twt.de/news/detail/connected-reality-die-superkonvergenz-unserer-welt-2.html (in German)
 Fraunhofer Application Center Industrial Automation INA: http://www.iosb.fraunhofer.de/servlet/is/12642/
 Video: Development of Intelligent Automatic Door System: http://www.youtube.com/watch?v=WhrLetrTSYA
“The Hitchhiker’s Guide to the Galaxy” is published by Heine-Verlag. ISBN: 978-3-453-40784-8