Books for you

We think about the information
fl ow actor by actor. We are primarily interested in the direction from an actor to
the system. We want to fi nd out what kind of services the actors request from our
system. If you can ??™ t think of any meaningful information just omit the information
fl ow. We don ??™ t have to do guesswork.
You can see the result of our thoughts in Figure 2.23 . The information fl ow
between the actor and the system is denoted by a black triangle on top of the
actor/system relationship. The triangle shows the information fl ow ??™ s direction.
Next to the triangle is the type of information, e.g., card data.
In our considerations about the information fl ow we found a new system
actor. We found that vibration forces from the moving car can affect our system.
This clearly shows us two things: First, SysML considers not only classic IT information,
but also physical objects. Second, immerging into detailed levels leads to
new fi ndings about the next higher level.
Also, the information itself is explicitly modeled.


Pages:
129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153