Application Specific PEID

The Application Specific PEID extends the PROMISE Core PEID by a PEID-specific interface. Access to data is not limited to key-content compositions, but the Application Specific PEID may provide a semantic method interface to read or write portions of the content of the PEID. Further, it may provide a semantic method interface for functionalities that are not addressable from the Core PEID and thereby extend the Core PEID.
The binding of a Core PEID with its Application Specific PEID(s) is static. It is conveyed by an appropriate semantic method of the Core PEID. Note that the Application Specific PEID may define the format and the semantics of portions of content of the PEID.
Let us try to provide an instructive example. Consider for instance the RFID-based Core PEID described above. Usually, RFID readers offer several options how they are configured. This is entirely irrelevant to PROMISE Data Services, but reader configuration is important in practice. The way how this issue will be solved in PROMISE is that reader configuration methods are implemented by an Application Specific PEID of the PEID, which is addressed from an RFID reader maintenance program.
The configuration methods usually differ from one RFID reader manufacturer to another, so that the implementation of the maintenance program depends on the RFID reader that is actually used. Since PROMISE Data Services will use the Core PEID’s functionalities, Core PEID-specific implementation issues are therefore hidden to PROMISE Data Services.
Let us consider the stress sensor as a second example. Here, the Core PEID provides content on a key-value basis, without necessarily providing the semantics of the sensor readings. This may or may not be desired by PROMISE Data Services. An Application Specific PEID grants access to the sensor readings in a semantic way by offering services like getTemperature, getTemperatureSeries, or getAverageTemperature.
So, on the backend layer, the use of the Application Specific PEID interface is not mandatory. It is more likely that PROMISE Data Services will only use the Core PEID interface in a rather non-semantic manner, while the Application Specific PEID will be of use for the top-level application layers. Moreover, we foresee that entirely different applications will use the Application Specific PEID for configuration and system monitoring tasks.
The semantics of the Core PAC Interface are described in detail in PROMISE Architecture Series, Volume 2: Architecture Reference: PROMISE Core PAC Interface.