Section: New Results

Self-describing objects

Participants : Michel Banâtre, Nebil Ben Mabrouk, Paul Couderc [contact] , Yann Glouche, Arnab Sinha.

Coupled objects enable basic integrity checking for physical objects, and use cases were demonstrated for security and logistics applications. In these applications, high reliability in the RFID reading infrastructure is assumed for the system to work. This suggest another idea for coupled objects: using control data structures distributed over the physical objects in order to improve the reliability of RFID reading protocols. This is the purpose of the Pervasive_RFID project, in collaboration with the IETR which is described in more details below 8.1.2 .

Another development in the line of the coupled objects principles are self-describing objects. While previous works enabled integrity checking over a set of physical objects, these mechanisms were limited in two aspects: expressiveness and autonomy. More precisely, coupled objects support the detection of special conditions (such as a missing element), but not the characterization of these conditions (such as describing the problem, identifying the missing element). Moreover, this compromises the autonomous feature of coupled objects, which would depend on external systems for analyzing these special conditions. Self-describing objects are an attempt to overcome these limitations, and to broaden the application perspectives of autonomous RFID systems.

The principle is to implement distributed data structure over a set of RFID tags, enabling a complex object (made of various parts) or a set of objects belonging to a given logical group to "’self-describe" itself and the relation between the various physical elements. Some applications examples includes waste management, assembling and repair assistance, prevention of hazards in situations where various products / materials are combined etc. The key property of self-describing objects is, like for coupled objects, that the vital data are self-"hosted" by the physical element themselves (typically in RFID chips), not an external infrastructure like most RFID systems. This property provides the same advantages as in coupled objects, namely high scalability, easy deployment (no interoperability dependence/interference), and limited risk for privacy.

However, given the extreme storage limitation of RFID chips, designing such systems is difficult:

• data structures must be very frugal in terms of space requirements, both for the structure and for the coding.

• Data structures must be robust and able to survive missing or corrupted elements if we want to ensure the self-describing property for a damaged or incorrect object.

An application of self-describing objects has been proposed in for waste management, in the context of the bin that think project 8.1.1 . A generic graph structure applicable to RFID systems for supporting self-describing objects is proposed in Arnab Sinha's thesis document (to be defended in April 2014).