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Table 1 System safety requirements in GIVEN-WHEN-THEN syntax for the door controller to mitigate the hazard “Passengers fall out of the train” connected to the train function “Open external passenger doors”. These requirements describe the behavior of the external train doors equipped with the lock mechanism that makes the door opening function safer. A slightly revised version of the table in [19]

From: Towards a Verification-Driven Iterative Development of Software for Safety-Critical Cyber-Physical Systems

Name Safety Requirement
SafeReq1 GIVEN the train is ready to run
  WHEN the driver requests to lock all external doors
  THEN the door controller shall close and lock all the external doors
SafeReq2 GIVEN an external door is locked
  WHEN the passenger requests to open the external door
  THEN the door controller shall keep the external door closed and locked
SafeReq3 GIVEN an external door is unlocked AND the train is at station
  WHEN the passenger requests to open an external door
  THEN the door controller shall open the external door
SafeReq4 GIVEN all external doors on the side of the train close to the platform are unlocked
  WHEN the driver requests to open all external doors
  THEN the door controller shall open all external doors on the side of the train close to the platform
SafeReq5 GIVEN the train approaches a station
  WHEN the driver requests to unlock all external doors that are on the train side close to the platform
  THEN the door controller shall unlock all external doors on the side of the train close to the platform
SafeReq6 GIVEN the train is running
  WHEN an external door is open
  THEN the door controller shall provide an alert