Merge pull request #14 from FlorianMerkle/patch-1

fixed typo in device_model.md

src/02_framework/device_model.md

@@ -16,7 +16,7 @@ The device model was built upon a reference architecture for IoT platforms. Fur
 
 ## Device Boundaries
 
-In order to distinguish between components belonging to an IoT device and components of the surrounding IoT ecosystem, it is necessary to first define the boundaries of an IoT device. An IoT device is generally encompassed by an enclosure of some kind, which (physically) separates device-internal lements from device-external elements.
+In order to distinguish between components belonging to an IoT device and components of the surrounding IoT ecosystem, it is necessary to first define the boundaries of an IoT device. An IoT device is generally encompassed by an enclosure of some kind, which (physically) separates device-internal elements from device-external elements.
 
 Interactions between internal and external elements are only possible via interfaces. Within this guide, these interfaces are not considered to be part of the enclosure. Instead, those interfaces will be categorized individually (see [Interfaces](#interfaces)).