1. Operational safety, a necessity

Over the past fifty years, we have witnessed extraordinary advances in the performance of many of the systems that surround us, such as automated production systems, transportation systems (airplanes, high-speed trains, automobiles), telecommunications systems (telephony, internet), and so on.

The high level of performance required would necessitate flawless operation. However, alongside improvements in performance, it must also be noted that these systems have become considerably more complex, which has led to an increase in the number of potential sources of failure. In addition, current economic imperatives impose increasingly short deadlines for bringing products to market or reaching operational status, without significant feedback on failures being available, especially in the case of entirely new devices.

These failures or malfunctions...