A Layered Architecture based on pRevisional Mechanisms (ALARM)

ALARM is a layered architecture suitable for designing systems based on the acquisition and elaboration of data coming from sensing devices (e.g., surveillance systems).

Each layer includes objects that model the “real world” at a specific abstraction level, from sensed data up to domain concepts.

ALARM is based on the following basic concepts:

• The system is structured in layers. Each layer includes objects that model the “real world” at a specific abstraction level, from raw data up to domain concepts; objects are located in spatial and temporal reference systems;
• Hypotheses are abductive inferences based on objects;
• The “intelligence” of each layer relies on the formulation of previsions about objects and on their verification against hypotheses coming from lower layers;
• Previsions have a time-dependent validity, therefore their verification is time-driven;
• Failure of the verification process generates an exception that is notified to the upper layer (upstream flow).
• A line of thought is a series of semantically linked previsions about the evolution of an object. Many lines of thought related to the same object may be formulated.
• The verification of a prevision may be delegated to the lower abstraction level (downstream flow);