Examples of Describing a System as a Transparent Box
Let's consider three types of descriptions using the example of a clock[1].
A functional description is an account of subsystems as role-based or functional objects. The functional description shows “how the system works internally.” For example, the functional diagram illustrates how a clock operates. Notice that this diagram does not include modules, since here we are interested in the functional parts of the clock. These parts demonstrate their functional or role-based behavior.
Constructive or physical modules are the objects assembled to form the clock system. A modular description or modular breakdown shows what the system is made of. As you can see, the modular diagram indicates many of the system’s constructive parts. This diagram does not clarify how the clock works, but it clearly shows how to assemble the clock from gears, springs, hands, and other modules.
The third description is about the locations in space where the system’s parts are situated. In other words, it is important to know where in the universe the system’s parts are located. This is a spatial breakdown. If the exact placement of the modules is unknown, the system will not function.
System levels are defined by functional breakdown—the main approach in systems thinking! That’s why functional breakdown is often called “system breakdown.” What about the others? Those are ordinary breakdowns. And, of course, we should not forget that there are also modular and spatial breakdowns.
As you can see, all systems at each system level interact with each other as functional objects. This interaction is described by the functional diagram. At the same system level, you can also identify specific physical objects that perform these functions (or play the role of functional objects). These physical objects are located somewhere in space. If we move to another system level, everything will be exactly the same.
For example, we can identify functional and physical objects and their locations at the subsystem level of a motor. Then, we can identify functional and physical objects and their locations at the level of the entire vehicle. At this point, we will no longer consider the structure of the motor; it will be a part of the vehicle system. Moreover, we can look at the motor system from a functional perspective—this functional object must deliver torque[2]. We can also view the motor system as a physical object—such as the BD-1324 gasoline engine. We can move up yet another level, where there will be other functional and physical objects and their locations.
The next example relates to the system of a person as a constructor, who can create successful systems in various projects. The constructor has functional behavior—life mastery. Life mastery consists of the following functional parts:
- thinking mastery or intellect;
- applied mastery.
Another example concerns the functional parts of the vehicle system. These would be the chassis, body, and engine. Here, in turn, you can also perform further system breakdown and examine the structure of the chassis, thereby identifying the next system level.