1. A surveillance system implementing an architecture and process to support real-time abnormal behavior assessment operations in a distributed scalable sensor network, the system comprising: an automated behavior model builder generating behavior models from sensor data; a plurality of abnormal behavior scoring engines operating concurrently to generate abnormal behavior assessment models by scoring the behavior models; and an execution performance manager performing fast switching of behavior models for said abnormal behavior scoring engines, wherein the execution performance manager performs fast switching between a first behavior model and a second behavior model based on a similarity between a first temporal-spatial descriptor of the first model and a second temporal-spatial descriptor of the second model, wherein said execution performance manager performs detection of abnormal behavior score distribution characteristic deviation by comparing a current abnormal behavior assessment model to a pre-recorded abnormal behavior assessment model, and selects a pre-recorded behavior model for said abnormal behavior scoring engines when the deviation exceeds a predetermined threshold.