Software Product Line Engineering Basics - Model-Driven and Software Product Line Engineering - page 24

sensors and actuators work together. The sensors are physical
devices that measure values of the environment and make
them available to the Smart-Home system. The actuators
activatethedeviceswhosestatecanbemonitoredandchanged.
All installed devices, including sensors and actuators, are
a part of the Smart-Home network. The status of devices
can be changed by inhabitants through the user interface,
remotely by using an Internet connection or by the system
using predefined policies. These policies let the system act
autonomously in case of certain events. For example, in case
of low indoor temperature, the windows close automatically;
in case of fire, the fire brigade is automatically called, and
so on.
The architectural structure of buildings (e.g. the number
of floors, rooms, or windows), the sensors and actuators as
well as other devices, their location inside the buildings, and
the policies, are specific for each Smart-Home system and
must be defined by the designers of the Smart-Home systems.
Thus, Smart-Home systems can be created with the necessary
softwarecomponentstorespondtotheparticularrequirements
of each Smart-Home owner. At runtime, the Smart-Home
system is then ready to respond to external or internal stimuli
depending on the defined structure of the building, its devices,
and the chosen policies.
In our example, Smart-Home systems must provide the
following functions:
- Climate control system. Climate control devices must be
orchestrated to keep the preferred temperature in the rooms of
the house.
- Security system. The door, the window sensors, and the
motion detectors should detect unauthorized entries into the
house.Ifanyattemptatintrusionisdetected,emergencyaction
must be taken.
- Energy saving. House devices should be orchestrated to
use the least amount of energy.